recent hypothesis proven 2022

October 4, 2022

Explorers of Quantum Entanglement Win 2022 Nobel Prize in Physics

Alain Aspect, John F. Clauser and Anton Zeilinger won the 2022 Nobel Prize in Physics for their work using entangled photons to test the quantum foundations of reality

By Lee Billings

vanbeets/Getty Images (medal)

This year’s Nobel Prize in Physics was awarded in equal parts to Alain Aspect of the University of Paris-Saclay, John F. Clauser of J. F. Clauser & Associates, and Anton Zeilinger of the University of Vienna, for their pathfinding work in quantum mechanics and quantum information science.

Working independently, each of the three researchers forged new experiments demonstrating and investigating quantum entanglement, the curious phenomenon in which two or more particles exist in a so-called entangled state. In this bizarre situation, an action taken on one of the particles can instantaneously ripple through the entire entangled assemblage, predicting the other particles’ behavior, even if they are far apart. If an observer determines the state of one such particle, its entangled counterparts will instantly reflect that state—whether they are in the same room as the observer or in a galaxy on the opposite side of the universe. Although this phenomenon has become an essential aspect of modern quantum technologies, it is so counterintuitive and seemingly impossible that Albert Einstein once famously derided it as “spooky action at a distance.”

The scientists’ work has collectively addressed core enigmas that were deeply investigated in the 1960s by Northern Irish physicist John Stewart Bell, who sought to understand what entanglement’s “spookiness” implies about the fundamental nature of reality. Could it be, as Einstein believed, that all objects—whether planets or particles—possess fundamental properties that can be discerned through precise observation? If so, quantum weirdness would only be an illusion arising from the failure of quantum mechanics to account for as-yet-undiscovered “hidden variables” inherent to the particles that populate the subatomic world. By preordaining the states of widely separated entangled particles before those particles were measured, hidden variables would neatly explain how they managed to reflect each other’s state without information traveling between them faster than the speed of light—a profound violation of one of the most fundamental tenets of physics. Einstein’s idea flew in the face of an alternative preferred by Niels Bohr, Erwin Schrödinger and other physicists, who rejected the notion of such hidden variables. Reality, they said, is inherently fuzzy, and particles only gain certain specific characteristics upon being measured.

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Expanding on a concept proposed some three decades prior by Einstein and his physicist colleagues Boris Podolsky and Nathan Rosen, in 1964 Bell showed that if hidden variables existed, their presence could be experimentally inferred through careful measurements of multiple pairs of entangled particles. When, for instance, such particles’ spins are measured along a varying directional axis (that is, not only “up” or “down” but also various states in between), certain correlations between the collective paired spins should be much stronger if they are dictated purely by quantum mechanics and correspondingly weaker if they are influenced by hidden variables. Performing this experiment could thus confirm that reality, at its heart, is purely quantum mechanical or instead reveal the presence of deeper, more fundamental layers of physical complexity. Such “Bell tests,” however, contained multiple potential loopholes that could confound their results. And across decades, legions of researchers ardently worked to close them.

Credit: Matthew Twombly; Source: Modified from TU Delft—A Loophole-Free Bell Test (based on text by Michel van Baal and graphics by Scixel). TU Delft, 2015

In 1969 Clauser was the first to conceive a practical Bell test, which involved measuring quantum entanglement by determining the polarization of entangled photon pairs launched in opposite directions. He then performed the experiment in 1972 alongside the late Stuart Freedman, who was then a graduate student, confirming that the photons acted in concert despite their physical separation. Clauser’s work indicated that hidden variables could not explain entanglement’s effects, suggesting that quantum theory remained intact as an essentially complete description of reality.

But the loopholes remained. And about 10 years later, after refining Clauser’s experiment, Aspect and his collaborators closed one of them by developing a way to switch the directions of entangled photon pairs in billionths of a second—after the photons had left their source but before they arrived at a detector. This ensured that the measurement settings that existed when the photons were emitted could not affect the ultimate result, greatly reinforcing the notion that hidden variables do not exist. Whatever fundamentally occurs during the measurement of entangled particles (still a topic of intense debate among scientists), Aspect’s work showed it does so within the confines of existing quantum theory. The last major loophole for Bell tests was closed in 2015  through the work of four different research groups.

Zeilinger and his colleagues greatly expanded the use and study of entangled quantum states. In 1997 they were one of two research groups to independently demonstrate a phenomenon called quantum teleportation, which uses entanglement to allow quantum states to be moved from one particle to another across arbitrary distances. (The other team was headed by Italian physicist Francesco De Martini.) Zeilinger’s group went on to achieve several more “firsts” in quantum information science. Today quantum teleportation has become central for nascent efforts to build a globe-spanning “ quantum Internet .” And Zeilinger collaborated on work that successfully used the technique to create China’s Micius spacecraft, the first quantum communications satellite .

The Nobel Prize in Physics 2022 was awarded jointly to Alain Aspect, John F. Clauser and Anton Zeilinger “for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science.” Credit: Niklas Elmehed © Nobel Prize Outreach

During the prize’s announcement, Eva Olsson, a member of the Nobel Committee for Physics, said Aspect’s, Clauser’s and Zeilinger’s work has “opened doors to another world, and it has also shaken the very foundations of how we interpret measurements.”

Collectively, the trio’s research has contributed greatly to quantum information science , the scientific field underpinning the ongoing race to develop practical devices and techniques that leverage quantum principles to achieve breakthroughs in computing, communications and cryptography.

“The work of Aspect, Clauser and Zeilinger provides the practical theoretical method and conclusive experimental measurements that underline the distinction between the quantum and classical worlds, showing that quantum objects can be related through entanglement in a way that is not possible with classical objects,” says Andrew Cleland, a quantum physicist at the University of Chicago. “Their work forms the fundamental basis for quantum computation and quantum communication.”

John Preskill, a leading quantum information scientist at the California Institute of Technology, notes that many mature technologies are already “quantum” in some sense: lasers, magnetic resonance imaging machines and multibillion-transistor computer chips all rely on quantum mechanics unfolding on subatomic scales. “But those technologies,” he says, “have only scratched the surface of how quantum theory has modified our view of what’s possible in the universe.”

And, Preskill adds, “the burgeoning investments in quantum technologies now occurring all over the world are building on scientific foundations which flow from the pioneering work of Bell, Clauser, Aspect and Zeilinger.”

In a press conference shortly after the announcement, Zeilinger expressed shock at being awarded the prize and acknowledged the influence of the late Helmut Rauch, who had been his academic adviser, as well as the “more than 100 young people who worked with me over the years and made this all possible.” Despite the myriad emerging applications for quantum entanglement, Zeilinger said that what most inspires him remains the mystery it still poses about the nature of reality. “Some of the fundamental questions—the very question ‘What does this really mean?’—in a basic way, are still unanswered in my eyes,” he said. “And that is an avenue for new research.”

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• 11 November 2022
• Correction 14 November 2022

Mathematician who solved prime-number riddle claims new breakthrough

• Davide Castelvecchi

You can also search for this author in PubMed   Google Scholar

A mathematician who went from obscurity to luminary status in 2013 for cracking a century-old question about prime numbers now claims to have solved another. The problem is similar to — but distinct from — the Riemann hypothesis, which is considered one of the most important problems in mathematics.

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Nature 611 , 645-646 (2022)

doi: https://doi.org/10.1038/d41586-022-03689-2

Updates & Corrections

Correction 14 November 2022 : This article has been amended to clarify that the formula Zhang claims to have proved is not the Landau-Siegel zeros conjecture, but a weaker version of it.

Zhang, Y. Preprint at https://arxiv.org/abs/2211.02515 (2022).

Zhang, Y. Preprint at https://arxiv.org/abs/0705.4306 (2007).

Zhang, Y. Ann. Math. 179 , 1121–1174 (2014).

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Breaking Down the Quantum Research That Earned Three Physicists the Nobel Prize

What they revealed could enable ultra-secure computing and new telescope technology

Will Sullivan

Daily Correspondent

On Tuesday, the Royal Swedish Academy of Sciences awarded the 2022 Nobel Prize in Physics to Alain Aspect , John Clauser and Anton Zeilinger for experiments in quantum science. Each will receive a third of the 10 million Swedish kronor (roughly $900,000) prize that accompanies the honor.

Their research laid the groundwork for ultra-secure communications and complex computing, and it demonstrated that quantum mechanics—the field that deals with the motion and interaction of the smallest particles—is fundamentally weird.

The three researchers conducted experiments that showed a special state called “entanglement,” when multiple tiny particles are linked, in a sense, so that what happens to one determines what happens to the others, even when they are separated by large distances, the Nobel committee wrote in a press release . When a scientist determines the state of a particle, all the others that are “entangled” with it will immediately take on the same state, regardless of where they are, even if they’re in a distant galaxy, writes Lee Billings for Scientific American .

Working independently, Clauser and Aspect proved this phenomenon can’t be explained by the typical laws of physics, and Zeilinger demonstrated that entanglement can “teleport” information between linked particles, Science ’s Adrian Cho reports.

The laureates’ work “has basically opened up this whole field of quantum information science and technologies,” Ronald Hanson , a quantum physicist at the Delft University of Technology in the Netherlands tells Science .

The experiments carried out by the Nobel prize winners were related to a debate between scientists in the 1930s over the nature of reality, writes Charlie Wood for Quanta . Albert Einstein believed that all objects have precisely defined properties, but the physicists Niels Bohr and Erwin Schrödinger argued a fundamental idea of quantum theory: that objects’ properties exist in a state of uncertainty until they are measured. (Think: Schrödinger’s cat is both alive and dead until you open the box.)

Einstein thought there was no state of uncertainty—even if a particle’s properties, such as an electron’s position, appeared to be uncertain, he argued that “hidden variables” unseen to scientists must define them. Otherwise, whatever influenced these particles would have to move faster than the speed of light to make an instantaneous change in their far-off entangled companions, and nothing can travel faster than light-speed, Einstein argued.

In the 1960s, physicist John Stewart Bell devised a thought experiment that relied on pairs of entangled particles to theoretically test Einstein’s idea, according to Science . Essentially, he imagined that two people simultaneously observed different particles that were entangled together. If hidden variables truly existed, the properties of entangled pairs would be correlated, but only up to a certain degree, writes Science .

In 1972, Clauser and colleagues carried out the first successful real-world version of Bell’s thought experiment. Because they measured super-strong correlations, their experiment suggested that quantum mechanics was right. This surprised Clauser, who had expected the results to support Einstein’s ideas, per Quanta.

A decade later, Aspect and colleagues conducted a more refined experiment that ruled out another potential explanation for entanglement, further supporting quantum theory. The last major loophole from Bell’s experiment was closed in 2015 , according to Scientific American .

If the idea of entanglement still sounds confusing—it is. Not even the laureates themselves know why it happens, report Seth Borenstein, Maddie Burakoff and Frank Jordans of the Associated Press (AP). Yet each of them, in their respective research, has proved that it exists.

“I have no understanding of how it works, but entanglement appears to be very real,” Clauser says to the AP.

Zeilinger and colleagues focused on studying the use of entangled particles, per Scientific American . In 1998, for example, his team entangled a photon from one entangled pair with a photon from a different entangled pair.

This finding has implications for transmitting information over long distances in a quantum internet, which could enable ultra-secure, encrypted communications, according to Science . These innovations might also lead to new sensors and telescopes , writes Nature News ’ Davide Castelvecchi and Elizabeth Gibney.

Entanglement has also aided preliminary work related to quantum computers, which carry out calculations too complex for conventional computers, per Nature News .

“The burgeoning investments in quantum technologies now occurring all over the world are building on scientific foundations, which flow from the pioneering work of Bell, Clauser, Aspect and Zeilinger,” John Preskill , a quantum information scientist at the California Institute of Technology, tells Scientific American .

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Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next .

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Einstein Proven Right Yet Again: Theory of General Relativity Passes a Range of Precise Tests

By Max Planck Institute for Astronomy January 1, 2022

Researchers have conducted a 16-year long experiment to challenge Einstein’s theory of general relativity. The international team looked to the stars — a pair of extreme stars called pulsars to be precise – through seven radio telescopes across the globe. Credit: Max Planck Institute for Radio Astronomy

The theory of general relativity passes a range of precise tests set by pair of extreme stars.

An international team of researchers from ten countries led by Michael Kramer from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has conducted a 16-year long experiment to challenge Einstein’s theory of general relativity with some of the most rigorous tests yet. Their study of a unique pair of extreme stars, so called pulsars, involved seven radio telescopes across the globe and revealed new relativistic effects that were expected and have now been observed for the first time. Einstein’s theory, which was conceived when neither these types of extreme stars nor the techniques used to study them could be imagined, agrees with the observation at a level of at least 99.99%.

More than 100 years after Albert Einstein presented his theory of gravity, scientists around the world continue their efforts to find flaws in general relativity. The observation of any deviation from General Relativity would constitute a major discovery that would open a window on new physics beyond our current theoretical understanding of the Universe.

The research team’s leader, Michael Kramer from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, Germany, says: “We studied a system of compact stars that is an unrivaled laboratory to test gravity theories in the presence of very strong gravitational fields. To our delight we were able to test a cornerstone of Einstein’s theory, the energy carried by gravitational waves , with a precision that is 25 times better than with the Nobel-Prize winning Hulse-Taylor pulsar , and 1000 times better than currently possible with gravitational wave detectors.” He explains that the observations are not only in agreement with the theory, “but we were also able to see effects that could not be studied before”.

Ingrid Stairs from the University of British Columbia at Vancouver gives an example: “We follow the propagation of radio photons emitted from a cosmic lighthouse, a pulsar, and track their motion in the strong gravitational field of a companion pulsar.

We see for the first time how the light is not only delayed due to a strong curvature of spacetime around the companion, but also that the light is deflected by a small angle of 0.04 degrees that we can detect. Never before has such an experiment been conducted at such a high spacetime curvature.”

This cosmic laboratory known as the “Double Pulsar” was discovered by members of the team in 2003. It consists of two radio pulsars which orbit each other in just 147 min with velocities of about 1 million km/h. One pulsar is spinning very fast, about 44 times a second. The companion is young and has a rotation period of 2.8 seconds. It is their motion around each other which can be used as a near perfect gravity laboratory.

Dick Manchester from Australia’s national science agency, CSIRO , illustrates: “Such fast orbital motion of compact objects like these — they are about 30% more massive than the Sun but only about 24 km across — allows us to test many different predictions of general relativity — seven in total! Apart from gravitational waves, our precision allows us to probe the effects of light propagation, such as the so-called “Shapiro delay” and light-bending. We also measure the effect of “time dilation” that makes clocks run slower in gravitational fields.

We even need to take Einstein’s famous equation E = mc 2 into account when considering the effect of the electromagnetic radiation emitted by the fast-spinning pulsar on the orbital motion. This radiation corresponds to a mass loss of 8 million tonnes per second! While this seems a lot, it is only a tiny fraction — 3 parts in a thousand billion billion(!) — of the mass of the pulsar per second.”

The researchers also measured — with a precision of 1 part in a million(!) — that the orbit changes its orientation, a relativistic effect also well known from the orbit of Mercury, but here 140,000 times stronger. They realized that at this level of precision they also need to consider the impact of the pulsar’s rotation on the surrounding spacetime, which is “dragged along” with the spinning pulsar. Norbert Wex from the MPIfR, another main author of the study, explains: “Physicists call this the Lense-Thirring effect or frame-dragging. In our experiment it means that we need to consider the internal structure of a pulsar as a neutron star . Hence, our measurements allow us for the first time to use the precision tracking of the rotations of the neutron star, a technique that we call pulsar timing to provide constraints on the extension of a neutron star.”

The technique of pulsar timing was combined with careful interferometric measurements of the system to determine its distance with high resolution imaging, resulting in a value of 2400 light years with only 8% error margin. Team member Adam fDeller, from Swinburne University in Australia and responsible for this part of the experiment, highlights: “It is the combination of different complementary observing techniques that adds to the extreme value of the experiment. In the past similar studies were often hampered by the limited knowledge of the distance of such systems.” This is not the case here, where in addition to pulsar timing and interferometry also the information gained from effects due to the interstellar medium were carefully taken into account. Bill Coles from the University of California San Diego agrees: “We gathered all possible information on the system and we derived a perfectly consistent picture, involving physics from many different areas, such as nuclear physics, gravity, interstellar medium, plasma physics and more. This is quite extraordinary.”

“Our results are nicely complementary to other experimental studies which test gravity in other conditions or see different effects, like gravitational wave detectors or the Event Horizon Telescope. They also complement other pulsar experiments, like our timing experiment with the pulsar in a stellar triple system, which has provided an independent (and superb) test of the universality of free fall”, says Paulo Freire, also from MPIfR.

Michael Kramer concludes: “We have reached a level of precision that is unprecedented. Future experiments with even bigger telescopes can and will go still further. Our work has shown the way such experiments need to be conducted and which subtle effects now need to be taken into account. And, maybe, we will find a deviation from general relativity one day…”

For more on this research, see Challenging Einstein’s Greatest Theory in 16-Year Experiment – Theory of General Relativity Tested With Extreme Stars .

Reference: “Strong-field Gravity Tests with the Double Pulsar” by M. Kramer et al., 13 December 2021, Physical Review X . DOI: 10.1103/PhysRevX.11.041050

More on SciTechDaily

Challenging einstein’s greatest theory in 16-year experiment – theory of general relativity tested with extreme stars.

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Is space pixelated the quest for quantum gravity, 10 crucial things that result from einstein’s theories of relativity, einstein’s theory of general relativity tested using black hole shadow, 7 comments on "einstein proven right yet again: theory of general relativity passes a range of precise tests".

If there’s enough gravity for time dilation to be significant, how much did that affect the perceived rotation and orbital speeds compared to actual speeds inside local reference frames of the pulsars?

It sounds like a very complex experiment to account for all the factors involved.

Unfortunately the interpretation as proof is as erroneous as Eddington’s! See vol 1 no.1 of “The Critical Rationalist”!

Às actual speed of the pulsars in the framee of referrence do not hampered,so another motion occuring simultaneously for same pulars system,say orbìal motion is subjected to time dilation;an effect equal to energy conserved in same secondary motion.

The concept of constrain motion fits good for the binary system of pulsars,simultaneously considering the surroundig stars’ effect.But basic fact differs is that no frame of reference is inertial.Again rotational bodies system for pulsar pair is is simply secondary.So time dialation is due to only gravitation of the pair,which is of secondary origin and for this energy has to expend by each pulsar.

Does the pulsar star connect to the orbit supermassive Black whole?????

Einstein’s theory of relativity is absolutely incorrect, and it is especially illogical that there are gravitational waves and gravitons! If gravity is the force of attraction of masses to each other, then each force should act in such a way that it also has its own gravitons and gravitational waves. The biggest possible deception of the explanation of gravity is that couple, space and time have some common attractive or “love” ties and so in their “survival” that couple makes a fabric, which is a “hunter” of matter and when it enters that network, “a newborn is born” ǴRAVITATION. This is truly a genocidal pill against understanding the laws of the universe !!! If this is accepted, it means that matter wanders through something that is not space and lasts and exists, which is not time and only when it enters Einstein’s network is “born” gravity. All these misconceptions and all the “scientific insects caught” in Einstein’s spider web show that none of them has any natural and logical connection with the processes of matter formation, its origin and the formation of gravity and electromagnetism. What I am presenting has evidence that can overturn more than 80% of erroneous theories to date, such as Einstein’s and even Lorentz’s transformations, not to mention that science knows nothing about the laws of motion of particles or celestial bodies. This is Copyright, Nikola Milović, who deals with the highest level of science in the history of mankind. !!

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October 19, 2021

Physicists announce results that boost evidence for new fundamental physics

by University of Cambridge

Results announced by the LHCb experiment at CERN have revealed further hints for phenomena that cannot be explained by our current theory of fundamental physics.

In March 2020, the same experiment released evidence of particles breaking one of the core principles of the Standard Model—our best theory of particles and forces—suggesting the possible existence of new fundamental particles and forces.

Now, further measurements by physicists at Cambridge's Cavendish Laboratory have found similar effects, boosting the case for new physics.

The Standard Model describes all the known particles that make up the universe and the forces that they interact through. It has passed every experimental test to date, and yet physicists know it must be incomplete. It does not include the force of gravity, nor can it account for how matter was produced during the Big Bang, and contains no particle that could explain the mysterious dark matter that astronomy tells us is five times more abundant than the stuff that makes up the visible world around us.

As a result, physicists have long been hunting for signs of physics beyond the Standard Model that might help us to address some of these mysteries.

One of the best ways to search for new particles and forces is to study particles known as beauty quarks. These are exotic cousins of the up and down quarks that make up the nucleus of every atom.

Beauty quarks don't exist in large numbers in the world around as they are incredibly short-lived—surviving on average for just a trillionth of a second before transforming or decaying into other particles. However, billions of beauty quarks are produced every year by CERN's giant particle accelerator, the Large Hadron Collider, which are recorded by a purpose-built detector called LHCb.

The way beauty quarks decay can be influenced by the existence of undiscovered forces or particles. In March, a team of physicists at LHCb released results showing evidence that beauty quarks were decaying into particles called muons less often than to their lighter cousins, electrons. This is impossible to explain in the Standard Model, which treats electrons and muons identically, apart from the fact that electrons are around 200 times lighter than muons. As a result, beauty quarks ought to decay into muons and electrons at equal rates. Instead, the physicists at LHCb found that the muon decay was only happening around 85% as often as the electron decay.

The difference between the LHCb result and the Standard Model was about three units of experimental error, or '3 sigma' as it is known in particle physics. This means there is only around a one in a thousand chance of the result being caused by a statistical fluke.

Assuming the result is correct, the most likely explanation is that a new force that pulls on electrons and muons with different strengths is interfering with how these beauty quarks decay. However, to be sure if the effect is real more data is needed to reduce the experimental error. Only when a result reaches the '5 sigma' threshold, when there is less than a one in a million chance of it being due to random chance, will particle physicists start to consider it a genuine discovery.

"The fact that we've seen the same effect as our colleagues did in March certainly boosts the chances that we might genuinely be on the brink of discovering something new," said Dr. Harry Cliff from the Cavendish Laboratory. "It's great to shed a little more light on the puzzle."

Today's result examined two new beauty quark decays from the same family of decays as used in the March result. The team found the same effect—the muon decays were only happening around 70% as often as the electron decays. This time the error is larger, meaning that the deviation is around '2 sigma', meaning there is just over a 2% chance of it being due to a statistical quirk of the data. While the result isn't conclusive on its own, it does add further support to a growing pile of evidence that there are new fundamental forces waiting to be discovered.

"The excitement at the Large Hadron Collider is growing just as the upgraded LHCb detector is about to be switched on and further data collected that will provide the necessary statistics to either claim or refute a major discovery," said Professor Val Gibson, also from the Cavendish Laboratory.

Provided by University of Cambridge

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Science News

Here’s why we care about attempts to prove the riemann hypothesis.

The latest effort shines a spotlight on an enduring prime numbers mystery

LINED UP   The Riemann zeta function has an infinite number of points where the function’s value is zero, located at the whirls of color in this plot. The Riemann hypothesis predicts that certain zeros lie along a single line, which is horizontal in this image, where the colorful bands meet the red.

Empetrisor/Wikimedia Commons ( CC BY-SA 4.0 )

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By Emily Conover

September 25, 2018 at 11:46 am

A famed mathematical enigma is once again in the spotlight.

The Riemann hypothesis, posited in 1859 by German mathematician Bernhard Riemann, is one of the biggest unsolved puzzles in mathematics. The hypothesis, which could unlock the mysteries of prime numbers, has never been proved. But mathematicians are buzzing about a new attempt.

Esteemed mathematician Michael Atiyah took a crack at proving the hypothesis in a lecture at the Heidelberg Laureate Forum in Germany on September 24. Despite the stature of Atiyah — who has won the two most prestigious honors in mathematics, the Fields Medal and the Abel Prize — many researchers have expressed skepticism about the proof. So the Riemann hypothesis remains up for grabs.

Let’s break down what the Riemann hypothesis is, and what a confirmed proof — if one is ever found — would mean for mathematics.

What is the Riemann hypothesis?

The Riemann hypothesis is a statement about a mathematical curiosity known as the Riemann zeta function. That function is closely entwined with prime numbers — whole numbers that are evenly divisible only by 1 and themselves. Prime numbers are mysterious: They are scattered in an inscrutable pattern across the number line, making it difficult to predict where each prime number will fall ( SN Online: 4/2/08 ).

But if the Riemann zeta function meets a certain condition, Riemann realized, it would reveal secrets of the prime numbers, such as how many primes exist below a given number. That required condition is the Riemann hypothesis. It conjectures that certain zeros of the function — the points where the function’s value equals zero — all lie along a particular line when plotted ( SN: 9/27/08, p. 14 ). If the hypothesis is confirmed, it could help expose a method to the primes’ madness.

Why is it so important?

Prime numbers are mathematical VIPs: Like atoms of the periodic table, they are the building blocks for larger numbers. Primes matter for practical purposes, too, as they are important for securing encrypted transmissions sent over the internet. And importantly, a multitude of mathematical papers take the Riemann hypothesis as a given. If this foundational assumption were proved correct, “many results that are believed to be true will be known to be true,” says mathematician Ken Ono of Emory University in Atlanta. “It’s a kind of mathematical oracle.”

Haven’t people tried to prove this before?

Yep. It’s difficult to count the number of attempts, but probably hundreds of researchers have tried their hands at a proof. So far none of the proofs have stood up to scrutiny. The problem is so stubborn that it now has a bounty on its head : The Clay Mathematics Institute has offered up $1 million to anyone who can prove the Riemann hypothesis.

Why is it so difficult to prove?

The Riemann zeta function is a difficult beast to work with. Even defining it is a challenge, Ono says. Furthermore, the function has an infinite number of zeros. If any one of those zeros is not on its expected line, the Riemann hypothesis is wrong. And since there are infinite zeros, manually checking each one won’t work. Instead, a proof must show without a doubt that no zero can be an outlier. For difficult mathematical quandaries like the Riemann hypothesis, the bar for acceptance of a proof is extremely high. Verification of such a proof typically requires months or even years of double-checking by other mathematicians before either everyone is convinced, or the proof is deemed flawed.

What will it take to prove the Riemann hypothesis?

Various mathematicians have made some amount of headway toward a proof. Ono likens it to attempting to climb Mount Everest and making it to base camp. While some clever mathematician may eventually be able to finish that climb, Ono says, “there is this belief that the ultimate proof … if one ever is made, will require a different level of mathematics.”

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Is the Hygiene Hypothesis True?

Did Covid shutdowns stunt kids' immune systems?

Caitlin Rivers

The hygiene hypothesis is the idea that kids need to be exposed to germs in order to develop healthy immune systems. We know that many common viruses did not circulate as widely during the pandemic, thanks to social distancing, masking, and other COVID mitigation measures. Are there downsides to those missed infections? 

In this Q&A, Caitlin Rivers speaks with Marsha Wills-Karp, PhD, MHS , professor and chair of Environmental Health and Engineering , about the role of household microbiomes, birth, and vaccines in the development of kids’ immune systems—and whether early exposure really is the best medicine.

This Q&A is adapted from Rivers’ Substack blog, Force of Infection .

I think there’s some concern among parents who have heard about the hygiene hypothesis that there is a downside to all those stuffy noses that didn’t happen [during the COVID-19 pandemic]. Are there any upsides to viral infections? Do they help the immune system in some meaningful way?

I don’t think so.

You mentioned the hygiene hypothesis, which was postulated back in the ‘80s. German scientists noticed that families with fewer children tended to have more allergic disease. This was interpreted [to mean] that allergic disease was linked to experiencing fewer infections. I have explored this idea in my research for a couple of decades now.

This phenomenon has helped us to understand the immune system, but our interpretation of it has grown and expanded—particularly with respect to viruses. Almost no virus is protective against allergic disease or other immune diseases. In fact, infections with viruses mostly either contribute to the development of those diseases or worsen them.

The opposite is true of bacteria. There are good bacteria and there are bad bacteria. The good bacteria we call commensals . Our bodies actually have more bacterial cells than human cells. What we’ve learned over the years is that the association with family life and the environment probably has more to do with the microbiome. So one thing I would say is sanitizing every surface in your home to an extreme is probably not a good thing. Our research team showed in animals that sterile environments don’t allow the immune system to develop at all. We don’t want that.

What does contribute to the development of the immune system, if not exposure to viruses?

There are a number of factors that we’ve associated with the hygiene hypothesis over the last 20 years, and these exposures start very early in life. Cesarean sections, which do not allow the baby to travel through the birth canal and get exposed to the mother’s really healthy bacterial content, is a risk factor for many different immune diseases. Getting that early seeding with good bacteria is critical for setting up the child going forward. Breastfeeding also contributes to the development of a healthy immune system.

There are other factors. Our diets have changed dramatically over the years. We eat a lot of processed food that doesn’t have the normal components of a healthy microbiome, like fiber. These healthy bacteria in our gut need that fiber to maintain themselves. They not only are important for our immune system but they’re absolutely critical to us deriving calories and nutrients from our food. All these things contribute to a healthy child.

We’ve also noticed that people who live on farms have fewer of these diseases because they’re exposed to—for lack of a better term—the fecal material of animals. And what we have found is that it’s due to these commensal bacteria. That is one of the components that help us keep a healthy immune system. Most of us will probably not adopt farm life. But we can have a pet, we can have a dog.

I think all the pet lovers out there will be pleased to hear that.

There’s a lot of evidence that owning a pet in early childhood is very protective.

What about the idea that you need to be exposed to viruses in early life because if you get them as an adult, you’ll get more severely ill? We know that’s true for chickenpox, for example. Do you have any concerns about that?

We should rely on vaccines for those exposures because we can never predict who is going to be susceptible to severe illness, even in early childhood. If we look back before vaccines, children under 4 often succumbed to infections. I don’t think we want to return to that time in history.

Let me just give you one example. There’s a virus called RSV, it’s a respiratory virus. Almost all infants are positive for it by the age of 2. But those who get severe disease are more likely to develop allergic disease and other problems. So this idea that we must become infected with a pathogenic virus to be healthy is not a good one.

Even rhinovirus, which is the common cold, most people recover fine. But there’s a lot of evidence that for somebody who is allergic, rhinovirus exposures make them much worse. In fact, most allergic or asthmatic kids suffer through the winter months when these viruses are more common.

And that’s particularly salient because there is a lot of rhinovirus and enterovirus circulating right now.

From my point of view, right now, avoiding flu and COVID-19 is a priority. Those are not going to help you develop a healthy immune response, and in fact, they can do a lot of damage to the lungs during that critical developmental time. Data [show] that children that have more infections in the first 6 months to a year of life go on to have more problems.

It’s always surprising to me when I look at the data of the fraction of time that young children spend with these common colds—and this is pre-pandemic—it’s not uncommon for kids to be sick 50% of the time. That feels right as a parent, but it’s startling.

The other thing people don’t know is that the GI tract is where you get tolerized to all of your foods, allergens and things. Without those healthy bacteria in your gut, you can’t tolerate common allergens.

How does that relate to the guidance that’s changed over the years—that you should withhold peanuts in early life and now you’re supposed to offer them in early life?

The guidance to delay exposure to peanuts didn’t consider the fact that oral exposure to peanuts was not the only exposure kids were getting. There were peanut oils in all kinds of skin creams and other things. So kids got exposed through their skin, but they had no gut protection—and the GI tract is important for a tolerant system. If you have a healthy immune response, you get tolerized in early life.

This concept is a little bit different for those families who may already have a predisposition to allergies. But for the general public, exposure is key to protecting them in early life.

I think some parents look at the guidance that you should now offer peanuts in early life and say, “Are we not doing that with rhinovirus by masking kids or improving ventilation?” How should people think about the development of the immune system for food allergies compared to infections?

The thing about rhinoviruses is that after recovering, you’re not protected from the next infection. There is no real immune protection there. Most of us suffer from colds throughout our whole life. Like I said, bacterial exposure is what’s key to priming the immune response. 

Also, we forget that a lot of kids die from the flu. Unlike COVID-19, where younger kids are not quite as susceptible to severe illness, that’s not true for flu. RSV, too, can be quite severe in young children and older adults.

Caitlin Rivers, PhD, MPH , is a senior scholar at the Johns Hopkins Center for Health Security and an assistant professor in Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health.

• Study Finds That Children’s Antibody Responses to COVID-19 Are Stronger Than Adults’
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Right again, Einstein: New snapshot of 1st black hole to be photographed confirms relativity

The new black hole image offers further confirmation for Albert Einstein's theory of general relativity.

In 2019, a team of scientists from the Event Horizon Telescope (EHT) Collaboration were the first to capture a close-up of a black hole .

Now, five years later, the team has released a new image of the black hole at the center of the galaxy Virgo A, dubbed Messier 87 (M87*).

Just like the first , these pictures show a dark shadow at the center of a bright golden ring. But the  brightness peak of the ring has shifted by about 30 degrees compared to the first shot, while the dark heart of the cosmic behemoth is unchanged.

These properties confirm Albert Einstein's theory of relativity , according to a study published on Jan. 18 in the journal Astronomy & Astrophysics .

RELATED: James Webb telescope discovers the oldest, most distant black hole in the universe

Relativity states that the laws of physics are the same no matter where you look in the universe. If true, this would mean that the diameter of M87*'s ring should remain the same from year to year as long as the black hole's mass has not changed — and that's exactly what the researchers found.

The black hole M87* is not consuming matter , also known as accreting, fast enough to increase its mass over the duration of a human lifetime. That means that the ring size remains mostly fixed, the researchers said.

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However, the swirl of flattened, fast-moving gas, plasma and dust known as an accretion disk that surrounds the black hole is constantly changing.

"While general relativity says the ring size should stay pretty fixed, the emission from the turbulent, messy accretion disk around the black hole will cause the brightest part of the ring to wobble around a common center," study co-author Britt Jeter , a postdoctoral fellow at Academia Sinica Institute for Astronomy and Astrophysics, said in the statement. "The amount of wobble we see over time is something we can use to test our theories for the magnetic field and plasma environment around the black hole."

— James Webb Telescope spots galaxies from the dawn of time that are so massive they 'shouldn't exist'

— Black holes may be swallowing invisible matter that slows the movement of stars

— What's the biggest black hole in the universe?

The first image of the black hole was captured using data collected prior to 2017, while this new shot uses data up until April 2018. To capture this image, scientists combined information from an array of telescopes, including several that were not used to snap the first photo, such as the Large Millimeter Telescope in Mexico and the Greenland Telescope .

"The inclusion of the Greenland Telescope in our array filled critical gaps in our earth-sized telescope," study co-author Rohan Dahale , a doctoral candidate at the Institute of Astrophysics of Andalusia  in Spain, said in the statement. "The 2021, 2022, and the forthcoming 2024 observations witness improvements to the array, fueling our enthusiasm to push the frontiers of black hole astrophysics."

Kiley Price is a former Live Science staff writer based in New York City. Her work has appeared in National Geographic, Slate, Mongabay and more. She holds a bachelor's degree from Wake Forest University, where she studied biology and journalism, and is pursuing a master's degree at New York University's Science, Health and Environmental Reporting Program.

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Scientists are still fleshing out Darwin’s theory of evolution

There can be no one unifying theory, writes Prof Jonathan Bard , while Nicholas Maxwell looks to the role of purposive actions and Pete Bibby says the fittest theory will survive

Stephen Buranyi misses some key points in his article ( Do we need a new theory of evolution?, 28 June ). Darwin saw novel speciation as resulting from natural selection acting on anatomical variants, but that simple skeleton needed fleshing out. It took a century of research, for example, for us to understand the importance of inheritance in very small populations if novel variants were to become predominant.

The major problems in understanding evolutionary change today are as follows. First, working out how anatomical variants form – and this is hard because we don’t yet have a full understanding of how normal embryology works (evolution, it has been claimed, is development gone wrong) and can only rarely recognise a favourable mutation. Second, unpicking the generally opaque processes of selection (there are at least four independent reasons why zebra stripes would be favoured). Third, understanding why substantial evolutionary change seems so slow, albeit that this is what the fossil record demonstrates. This is the topic that excites the community that Buranyi discusses, even though modern molecular genetics and systems biology show that heritable novelties can form more rapidly than they realise.

The deeper problem is that evolutionary change involves the complete scale of nature, from DNA mutation to climate change, so of course there can be no unifying theory. The difficulty for scientists is that convincing experimentation is hard and slow. Prof Jonathan Bard Oxford

Those biologists who are critical of current Darwinian orthodoxy and who want to modify the theory in the direction of the “extended Darwinian synthesis” need to take things further. They need to recognise that all living things are purposive. They pursue goals – without necessarily being aware of it – the ultimate goal being survival and reproductive success.

Purposive action can, in a multitude of ways, influence what has survival value – and thus influence the future course of evolution. Purposive action that results in living in a new environment, or pursuing new kinds of food, can change what has survival value for that creature and its offspring, and thus can influence the future course of evolution. Foxes hunting rabbits breed rabbits better able to escape; and rabbits escaping breed foxes better able to catch them.

Above all, when animals make discoveries and learn from one another, cultural evolution becomes possible, and that can have a massive impact on subsequent evolution, as the case of human evolution, and the evolution of language, show.

We need a new, unified version of Darwinian theory that recognises that the purposive actions of living things play a vital role in evolution. This is very definitely not Lamarckism , although too many biologists have denied the Darwinian role of purposive action in evolution for fear that that commits one to Lamarckism. For more about this, see chapter 6 of my 2020 book Our Fundamental Problem: A Revolutionary Approach to Philosophy. Nicholas Maxwell Emeritus reader, science and technology studies, University College London

Surely there’s no problem with having several conflicting theories of evolution? Eventually the fittest will survive. Pete Bibby Sheffield

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A Decisive Blow to the Serotonin Hypothesis of Depression

An exhaustive new review debunks the “chemical imbalance” theory of depression..

Posted July 19, 2022 | Reviewed by Vanessa Lancaster

• What Is Depression?
• Find a therapist to overcome depression
• Surveys indicate that 85-90 percent of the public believes low serotonin or a chemical imbalance causes depression.
• Among 237 psychology students interviewed, 46 percent had heard the chemical imbalance explanation from a physician.
• The serotonin hypothesis has been challenged repeatedly and found wanting, even as it remains popular and influential.
• A comprehensive, well-powered, high-quality umbrella review now determines that the theory is “not empirically substantiated.”

Almost as soon as it was floated in 1965 by Harvard psychiatrist Joseph Schildkraut, the serotonin hypothesis of depression —reduced and simplified by pharma marketing to the “chemical imbalance” theory of depression and anxiety —has been subject to critical research and found wanting.

The poor standing of the hypothesis in the scientific literature, however, barely dented its afterlife in textbooks, across clinical and treatment settings, and on mental health apps and websites. Nor has it dispelled the continued use of the phrase as “shorthand” between doctors and patients and in everyday settings, including for quite different mental states and conditions .

The “Chemical Imbalance” Metaphor Takes Root

Revisiting the history of this controversy raises several still-relevant details. In December 2005, as advertising for SSRI antidepressants flooded American magazines, talk shows, and network TV, the result of multibillion-dollar campaigns pitched in this case directly to consumers, Florida-based professors and researchers Jeffrey Lacasse and Jonathan Leo asked pointedly in PLoS Medicine, “Are the claims made in SSRI advertising congruent with the scientific evidence?”

The answer in “Serotonin and Depression: A Disconnect Between the Advertisements and the Scientific Literature,” their well-researched article, was a resounding no. The resulting “incongruence,” they determined, was “remarkable and possibly unparalleled.”

Lacasse and Leo found repeated evidence that the U.S. Food and Drug Administration had approved the marketing of SSRIs with two phrases still heavily in the subjunctive—that depression “ may be due to a serotonin deficiency” and that SSRI efficacy, “modestly” outcompeting placebo , was “ presumed to be linked to potentiation of serotonergic activity.” However, the research itself could not identify the precise mechanism.

The FDA had accepted aspirational language that the drugs “help to restore the brain’s chemical balance” and “bring serotonin levels closer to normal,” even though both claims were, and remain, scientifically meaningless.

“There is no such thing as a scientifically established correct ‘balance’ of serotonin,” Lacasse and Leo cautioned more than a decade ago, joining numerous other experts then and now. Additionally, both aspirational claims rest on a hypothesis that follow-up studies would end up contradicting repeatedly. In short, both the hypothesis and the expensive marketing that pushed it into American living rooms rested on a hedge: “Scientists believe that it could be linked with an imbalance of a chemical in the brain called serotonin.”

A Multibillion-Dollar Error

The hedge proved highly effective, even though, as David Healy explained in 2015 in “Serotonin and Depression,” in the BMJ, in practice, it entailed embracing or tacitly accepting “the marketing of a myth.” Through further oversimplification, a revised metaphor of a “chemical imbalance” took root as folk wisdom for multiple, dissimilar conditions listed in the DSM .

Returning to the controversy in “Antidepressants and the Chemical Imbalance Theory of Depression” (2015), Lacasse and Leo found that while the marketing had shifted emphasis from “correcting imbalances” to “‘adjusting’ or ‘affecting’ neurotransmitter levels,” leading psychiatrists were if anything, more wedded to the “chemical imbalance” metaphor than before.

Some had taken to the airwaves to say that it simplified communication with their patients. Daniel Carlat, the editor of The Carlat Psychiatry Report, explained on National Public Radio when asked what we know about psychiatric medication :

We don’t know how the medications actually work in the brain…. I’ll often say something like the way Zoloft works, is, it increases the level of serotonin in your brain (or synapses, neurons) and, presumably, the reason you’re depressed or anxious is that you have some sort of a deficiency. And I say that [chuckles] not because I really believe it, because I know the evidence really isn’t there for us to understand the mechanism—I think I say that because patients want to know something. And they want to know that we as physicians have some basic understanding of what we’re doing when we’re prescribing medications. They certainly don’t want to know that a psychiatrist essentially has no idea how these medications work (Qtd. in Lacasse and Leo).

The point in reproducing Carlat (who has made several such admissions on national media) was not to single him out but to stress how widespread the thinking and practice he shared so candidly. In 2007, as Lacasse and Leo pointed out, Frances, Lysaker, and Robinson found that among 237 psychology students interviewed, “46 percent had heard the chemical imbalance explanation from a physician.”

Inevitably, the problem of spreading false scientific information dovetails with that of medical ethics and the risk of enabling medically-induced harms. Because physicians swear to uphold the Hippocratic oath Primum non nocere (“First Do No Harm”), Lacasse and Leo questioned “the ethics of telling a falsehood to patients because you think it is good for them.”

They asked more broadly of those repeating the discredited hypothesis, whether as metaphor or oversimplification: “Do you believe it is ethical to present a falsified scientific theory as a fact to a patient? What are the possible negative effects of doing so?”

A significant consequence they anticipated at the time was that patients would realistically “conclude that they have been misled.”

Cut to the Present-day

A major new review of the research—the first of its kind exhaustively reviewing the evidence, published today in the journal Molecular Psychiatry —reaches a strikingly similar conclusion. In “The Serotonin Theory of Depression: A Systematic Umbrella Review of the Evidence,” University College London Psychiatry Professor Joanna Moncrieff and a team of five other top European researchers found “there is no evidence of a connection between reduced serotonin levels or activity and depression.”

The peer-reviewed umbrella review—representing one of the highest forms of evidence in scientific research—was extrapolated from meta-analyses and systematic reviews on depression and serotonin levels, receptors, and transporters involving tens of thousands of participants.

Although “the serotonin hypothesis of depression is still influential,” Moncrieff and coauthors noted, citing widely adopted textbooks published as recently as 2020 and surveys indicating that “85-90 percent of the public believes that depression is caused by low serotonin or a chemical imbalance,” the primary research indicates there is “no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations.”

Among other key findings:

• “Research on serotonin receptors and the serotonin transporter, the protein targeted by most antidepressants, found weak and inconclusive evidence suggestive of higher levels of serotonin activity in people with depression.” Widespread use of antidepressants is seen as the likely cause.
• The researchers also looked at studies where serotonin levels had been “artificially lowered in hundreds of people” (by depriving their diets of the necessary amino acid that makes serotonin) and found that “lowering serotonin in this way did not produce depression in hundreds of healthy volunteers,” according to a 2007 meta-analysis and several recent studies.
• Numerous other reviews on re-examination were found to provide weak, inconsistent, or nonexistent evidence of a connection between serotonin and depression.
• The researchers also probed well-powered studies involving tens of thousands of patients that focused on gene variation, including the gene for the serotonin transporter. These found “no difference in the genes between people with depression and healthy controls.” As such, “high-quality genetic studies effectively exclude an association between genotypes related to the serotonin system and depression, including a proposed interaction with stress.”
• The researchers also looked at “the effects of stressful life events and found that these exerted a strong effect on people’s risk of becoming depressed—the more of these a person had experienced, the more likely they were to be depressed.”

Legacy Effects of a Discredited Theory

“The popularity of the chemical imbalance idea of depression has coincided with a huge increase in the use of antidepressants,” note Moncrieff and coauthor Mark A. Horowitz in the study’s press release. “Prescriptions for antidepressants have sky-rocketed since the 1990s, going from being rare to a situation now where one in six adults in England and 2 percent of teenagers are prescribed an antidepressant in a given year.”

The practical ramifications of the umbrella review are thus vast and consequential, involving millions of people across multiple countries because the findings are tied to a discredited theory that is still fueling mass prescribing on a global basis.

Moncrieff explained in the press release:

Patients should not be told that depression is caused by low serotonin or by a chemical imbalance and they should not be led to believe that antidepressants work by targeting these hypothetical and unproven abnormalities. In particular, the idea that antidepressants work in the same way as insulin for diabetes is completely misleading. We do not understand what antidepressants are doing to the brain exactly, and giving people this sort of misinformation prevents them from making an informed decision about whether to take antidepressants or not.

Invited to extrapolate the review’s findings for Psychology Today, Moncrieff added:

Antidepressant use has reached epidemic proportions across the world and is still rising, especially among young people. Many people who take them suffer side effects and withdrawal problems that can be really severe and debilitating. A major driver of this situation is the false belief that depression is due to a chemical imbalance. It is high time to inform the public that this belief is not grounded in science.

Frances CM, Lysaker PH, and Robinson RP. (2007) The “Chemical Imbalance” Explanation for Depression: Origins, Lay Endorsement, and Clinical Implications.” Professional Psychology: Research and Practice 38(4), 411-20. [ Link ]

Healy, D. (2015) Serotonin and Depression. BMJ 350, h1771 [ Link ]

Lacasse JR and Leo J. (2005) Serotonin and Depression: A Disconnect between the Advertisements and the Scientific Literature. PLoS Medicine 2.12 e392. [ Link ]

Lacasse JR and Leo J. (2015) Antidepressants and the Chemical Imbalance Theory of Depression: A Reflection and Update on the Discourse (with Responses from Ronald Pies and Daniel Carlat). Behavior Therapist 38: 206-13 & 260-66. [ Link ]

Moncrieff J, Cooper RE, Stockmann T, Amendola S, Hengartner MP, and Horowitz, MA. (7.20.2022). “The Serotonin Theory of Depression: A Systematic Umbrella Review of the Evidence.” Molecular Psychiatry. DOI 10.1038/s41380-022-01661-0 [ Link ]

Christopher Lane, Ph.D., is a Professor Emeritus of Medical Humanities at Northwestern University.

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