Tag: quantum mechanics

‘Dark photon’ theory of light aims to take down the famous double-slit experiment, upending quantum physics

For centuries, most scientists have shared the belief that light behaves as both a wave and a particle. This idea, then, became the central component to quantum theory, sprouting the field of science known as quantum mechanics.

The double-slit experiment supported the idea, showing bright and dark bands that indicated wave-like interference. But now, a new study suggests that this experiment might not lock us into seeing light as a wave.

According to the experts, we can interpret those interference bands using quantum particles alone.

The research was led by Gerhard Rempe, the director of the Max Planck Institute for Quantum Optics. He teamed up with collaborators at Federal University of São Carlos and ETH Zurich for the study.

Modern physics and our view of light

In 1801, Thomas Young introduced an experiment by shining light through two narrow openings to produce intersecting fringes on a screen. His findings led many to conclude that light must be a wave.

A century later, quantum mechanics began to take shape, revealing that quantum particles like electrons could mimic wave-like light interference too.

Albert Einstein’s work on the photoelectric effect showed that light travels in discrete packets called photons. Niels Bohr then elaborated on wave-particle duality, ushering in one of the cornerstones of modern physics.

Dark and visible photons

The new approach from the research team explores the concept of bright and dark modes.

In their view, interference patterns can emerge from combining “detectable” and “undetectable” photon states. These bright states interact with an observer, while dark states remain hidden.

Such hidden photons might linger at places where we would normally think the light cancels out. Observers who try to track the path of these photons alter the state, flipping what was dark into bright or vice versa.

From this perspective, the light pathways can be viewed as quantum superpositions, rather than purely classical wave interference.

Keep reading

Laser Light Transformed Into a Supersolid in Groundbreaking Experiment

An international team of physicists has transformed laser light into a supersolid, marking an entirely new process for achieving this mysterious state of matter.

On the quantum level, matter often exhibits strange behaviors, and the supersolid state is one of the most counterintuitive examples. In this state, atoms arrange into a crystal lattice like a solid but also flow without friction, a property typically associated with liquids.

The Quest to Understand Supersolids

Scientists first proposed the idea of a solid that could demonstrate fluid-like flow in the 1960s, with theoretical exploration intensifying in the 1970s.

Helium was initially considered the most promising candidate for achieving this exotic phase of matter. However, early experiments attempting to produce a solid with superfluid properties yielded disappointing results. In the 1980s, physicist John Goodkind used ultrasound techniques to identify anomalies in matter that suggested supersolids might be feasible.

By the 2000s, new experimental data provided stronger hints of supersolid behavior, though some findings conflicted with theoretical predictions, making the state even more elusive.

Creating a Supersolid With Laser Light

For decades, researchers believed that achieving a supersolid state required ultracold atomic Bose-Einstein condensates combined with electromagnetic fields. This method, which was only successfully demonstrated in recent years, produced a material structured like table salt but also capable of flowing.

The latest research, however, takes an entirely different approach, creating a supersolid without using atoms at all.

The team began with a piece of gallium oxide designed with precise ridges to interact with an incoming laser beam. When the laser light struck the semiconductor’s ridges, it produced a quasiparticle known as a polariton. The shape of the ridges then constrained the polariton’s motion, forcing it into a supersolid state.

Keep reading

Scientists Produced a Particle of Light That Simultaneously Accessed 37 Different Dimensions

Classical and quantum mechanics don’t really get along as the science of the subatomic can get, well, weird. Take, for instance, quantum entanglement, which says that the state of one particle can be determined by examining the state of its entangled pair regardless of distance. This strange fact flies in the face of classical physics, and even led Albert Einstein to famously describe this quantum quirk as “spooky action at a distance.”

This is what is known as “quantum nonlocality,” where objects are influenced across distances (seeming beyond the speed of light) whereas classical physics follows local theory, the idea that objects are influenced by their immediate surroundings. This is a pretty sharp divide as explained by the famous no-go theorem known as the Greenberger–Horne–Zeilinger (GHZ) paradox, which essentially details how quantum theory cannot be described by local realistic description.

Named for the physicists who described the paradox in 1989, GHZ-type paradoxes show that when particles can only be influenced by proximity they produce mathematical impossibilities. As New Scientist reports, the paradox can even be expressed through a calculation where 1 equals -1. This paradox is useful in showing how quantum properties can not be described using classical means, but a new paper published in the journal Science Advances, decided to see just how strange these paradoxes could get.

Keep reading

Team presents first demonstration of quantum teleportation over busy internet cables

Northwestern University engineers are the first to successfully demonstrate quantum teleportation over a fiberoptic cable already carrying internet traffic.

The discovery introduces the new possibility of combining quantum communication with existing internet cables—greatly simplifying the infrastructure required for distributed quantum sensing or computing applications.

The study is published on the arXiv preprint server and is due to appear in the journal Optica.

“This is incredibly exciting because nobody thought it was possible,” said Northwestern’s Prem Kumar, who led the study. “Our work shows a path towards next-generation quantum and classical networks sharing a unified fiberoptic infrastructure. Basically, it opens the door to pushing quantum communications to the next level.”

An expert in quantum communication, Kumar is a professor of electrical and computer engineering at Northwestern’s McCormick School of Engineering, where he directs the Center for Photonic Communication and Computing.

Only limited by the speed of light, quantum teleportation could make communications nearly instantaneous. The process works by harnessing quantum entanglement, a technique in which two particles are linked, regardless of the distance between them. Instead of particles physically traveling to deliver information, entangled particles exchange information over great distances—without physically carrying it.

“In optical communications, all signals are converted to light,” Kumar explained. “While conventional signals for classical communications typically comprise millions of particles of light, quantum information uses single photons.”

Before Kumar’s new study, conventional wisdom suggested that individual photons would drown in cables filled with the millions of light particles carrying classical communications. It would be like a flimsy bicycle trying to navigate through a crowded tunnel of speeding heavy-duty trucks.

Kumar and his team, however, found a way to help the delicate photons steer clear of the busy traffic. After conducting in-depth studies of how light scatters within fiberoptic cables, the researchers found a less crowded wavelength of light to place their photons. Then, they added special filters to reduce noise from regular internet traffic.

“We carefully studied how light is scattered and placed our photons at a judicial point where that scattering mechanism is minimized,” Kumar said. “We found we could perform quantum communication without interference from the classical channels that are simultaneously present.”

Keep reading

Physicists Baffled by Odd Quasiparticle That Seems to Have No Mass—Until It Changes Direction

Scientists report the first known observation of a variety of quasiparticle that exhibits a very peculiar behavior: it appears to have mass, but only while moving in one direction.

Scientists at Pennsylvania State University recently succeeded in detecting the unusual quasiparticle while conducting studies involving a semi-metallic crystalline material. Known as a semi-Dirac fermion, this unique formation of particles was first theorized more than a decade ago, but until now had never been directly observed.

The discovery potentially paves the way toward future advances in a range of emerging technologies that include power storage and novel forms of sensor technologies.

Detecting a Novel Quasiparticle

Quasiparticles are small collections of particles that normally appear within crystal lattices or under other special conditions, which generally possess both momentum and position, and under certain conditions may also be considered particles.

Discovering a novel quasiparticle like a semi-Dirac fermion had not been something Yinming Shao, assistant professor of physics at Penn State and lead author of a new paper revealing the discovery, had anticipated when he and his colleagues began experimenting with ZrSiS, a semi-metal crystal material that became the focus of their efforts.

“We weren’t even looking for a semi-Dirac fermion when we started working with this material, but we were seeing signatures we didn’t understand—and it turns out we had made the first observation of these wild quasiparticles that sometimes move like they have mass and sometimes move like they have none.”

Particles Without Mass

More than a century ago, Einstein’s theory of general relativity predicted that anything moving at the speed of light will have no mass. Because of this, physicists already recognize that a particle can essentially be massless under certain circumstances, namely when its energy comes entirely from its motion. Under such conditions, particles are recognized as manifestations of energy moving at the speed of light, such as in the case of photons.

However, quasiparticles moving through solid materials like crystalline structures can sometimes behave differently. In the observations of the Penn State research team, this apparently resulted in the appearance of particles that have mass in only one direction.

Beginning in 2008, it was initially predicted that mass-shifting properties might be observed in certain kinds of quasiparticles, which provided the theoretical framework for semi-Dirac fermions. Based on these initial predictions by scientists with the University of California, Davis and Université Paris Sud in France, such quasiparticles would seemingly be massless when moving in one direction but would almost paradoxically appear to possess mass when moving in another direction.

Shao and the Penn State team happened upon the discovery of such bizarre quasiparticle behavior while utilizing what is known as magneto-optical spectroscopy, which allows researchers to observe infrared light reflected off materials that are placed under the influence of strong magnetic fields.

Keep reading

Groundbreaking Study Affirms Quantum Basis for Consciousness: A Paradigm Shift in Understanding Human Nature

A groundbreaking study has provided experimental evidence suggesting a quantum basis for consciousness.

By demonstrating that drugs affecting microtubules within neurons delay the onset of unconsciousness caused by anesthetic gases, the study supports the quantum model over traditional classical physics theories. This quantum perspective could revolutionize our understanding of consciousness and its broader implications, potentially impacting the treatment of mental illnesses and our understanding of human connection to the universe.

Exploring the Quantum Basis of Consciousness

For decades, one of the most fundamental and vexing questions in neuroscience has been: what is the physical basis of consciousness in the brain? Most researchers favor classical models, based on classical physics, while a minority have argued that consciousness must be quantum in nature, and that its brain basis is a collective quantum vibration of “microtubule” proteins inside neurons.

New research by Wellesley College professor Mike Wiest and a group of Wellesley College undergraduate students has yielded important experimental results relevant to this debate, by examining how anesthesia affects the brain. Wiest and his research team found that when they gave rats a drug that binds to microtubules, it took the rats significantly longer to fall unconscious under an anesthetic gas. The research team’s microtubule-binding drug interfered with the anesthetic action, thus supporting the idea that the anesthetic acts on microtubules to cause unconsciousness.

“Since we don’t know of another (i.e,. classical) way that anesthetic binding to microtubules would generally reduce brain activity and cause unconsciousness,” Wiest says, “this finding supports the quantum model of consciousness.”

Keep reading

BIZARRE TACHYONS THAT MAY BE ABLE TO SEND DATA BACK IN TIME COULD BE RECONCILED WITH SPECIAL RELATIVITY

Tachyons, a mysterious variety of hypothetical particles capable of exceeding light speed, could play a more significant role in our understanding of the universe and its causal structure than scientists previously realized.

Not only have tachyons been revealed to be potentially compatible with Einstein’s special theory of relativity, but now, according to an international collaboration of physicists from the University of Warsaw and the University of Oxford, these curious particles could also help shed light on remaining questions regarding our understanding of the quantum world.

EXCEEDING THE UNIVERSAL SPEED LIMIT

Tachyons, which derive their name from the Greek word tachýs, meaning fast or quick, are theorized to exist under conditions where their minimum speed would be the speed of light. This effectively means that they should only be capable of traveling at velocities that exceed this universally recognized speed limit.

Ordinary particles, by comparison, move at subluminal or slower than light speeds. As Einstein’s theory of relativity dictates, the universal laws of physics prevent anything from being capable of accelerating to the speed of light from a slower speed. The same isn’t necessarily true for tachyons, though, since they are theorized to be born at speeds that already exceed light. Hence, the opposite would seem to be the case for these unusual particles, which hypothetically should be incapable of slowing down to light speed or slower speeds.

The idea of such superluminal particles has its origins in theoretical studies conducted back in the 1960s by physicist Gerald Feinberg. Although no experimental evidence has ever confirmed their existence, a theoretical framework for how these proposed particles might come to be has been developed over the decades, occasionally resulting in some rather strange paradoxes.

Among these is a curiosity that arises from their superluminal travel speeds, which indicates that tachyons may effectively be capable of sending information backward in time, giving rise to bizarre conditions under which cause and effect could theoretically become reversed.

However, new research is revealing that despite the implications of their existence, these bizarre hypothetical particles may be compatible with the special theory of relativity and could also help offer physicists significant new insights into quantum theory.

The new findings could potentially also upend long-held notions about the unlikelihood of superluminal particles, suggesting that tachyons might even play a crucial role in the formation of matter.

Keep reading

Researchers demonstrate how to build ‘time-traveling’ quantum sensors

The idea of time travel has dazzled sci-fi enthusiasts for years. Science tells us that traveling to the future is technically feasible, at least if you’re willing to go near the speed of light, but going back in time is a no-go. But what if scientists could leverage the advantages of quantum physics to uncover data about complex systems that happened in the past?

New research indicates that this premise may not be that far-fetched. In a paper published June 27, 2024, in Physical Review Letters, Kater Murch, the Charles M. Hohenberg Professor of Physics and Director of the Center for Quantum Leaps at Washington University in St. Louis, and colleagues Nicole Yunger Halpern at NIST and David Arvidsson-Shukur at the University of Cambridge demonstrate a new type of quantum sensor that leverages quantum entanglement to make time-traveling detectors.

Murch describes this concept as analogous to being able to send a telescope back in time to capture a shooting star that you saw out of the corner of your eye. In the everyday world, this idea is a non-starter. But in the mysterious and enigmatic land of quantum physics, there may be a way to circumvent the rules. This is thanks to a property of entangled quantum sensors that Murch refers to as “hindsight.”

The process begins with entanglement of two quantum particles in a quantum singlet state—in other words, two qubits with opposite spin—so that no matter what direction you consider, the spins point in opposing directions. From there, one of the qubits—the “probe,” as Murch calls it—is subjected to a magnetic field that causes it to rotate.

Keep reading

CERN EXPERIMENT REVEALS “SPOOKY ACTION AT A DISTANCE” PERSISTS BETWEEN TOP QUARKS

Quantum entanglement in top quarks has been demonstrated, according to physicists at CERN who say the discovery offers new insights into the behavior of fundamental particles and their interactions at distances that cannot be attained by light-speed communication.

The research, led by University of Rochester professor Regina Demina, extends the phenomenon known as “spooky action at a distance” to the heaviest particles recognized by physicists and offers important new insights into high-energy quantum mechanics.

Initially discovered almost three decades ago, top quarks are the most massive elementary particles that have been observed. The mass of these unique particles originates from their coupling to the Higgs boson, the famous particle predicted in theory regarding the unification of the weak and electromagnetic interactions. According to the Standard Model of particle physics, this coupling is the largest that occurs at the scale of the weak interactions and those above it.

In the past, quantum entanglement has been observed in stable particles, including electrons and photons. In their new research, Demina and her team demonstrate entanglement between unstable top quarks and their antimatter counterparts, revealing spin correlations that occur over distances that extend beyond the transfer of information at light speed.

The findings present new challenges to existing models and expand our understanding of particle behavior at extreme energies. 

The experiment was conducted at the European Center for Nuclear Research (CERN) as part of the Compact Muon Solenoid (CMS) Collaboration. CERN is home to the famous Large Hadron Collider (LHC), a device that propels high-energy particles at speeds nearing those of light across a 17-mile underground track.

Given the amount of energy required for the production of top quarks, such processes can only be achieved at facilities like CERN. The results of Demina’s recent study could help to shed some light on how long entanglement persists, as well as whether it can be extended to “daughter” particles or decay products. The research also may help determine whether entanglement between particles can be broken.

Presently, it is believed that the universe was in an entangled state following its initial fast expansion stage. The revelation of entanglement in top quarks may help scientists like Demina better understand what factors may have contributed to the quantum connection in our world becoming diminished over time, ultimately leading to the state in which our reality exists today.

Keep reading

Scientists Are Searching the South Pole to See if Quantum Gravity Actually Exists

Within physics, there are two enormous foundational systems—quantum mechanics and general relativity—that have been like Macs and PCs for decades. Over time, scientists on both sides have worked toward the other side, because anyone who wants to explain the entire universe has to make the two foundations work together. And, like any decent computer lab, a unifying theory has to be truly cross-platform.

In new research, researchers from the University of Copenhagen’s Niels Bohr Institute (NBI)—alongside 58 other member universities— revealed the secrets of 300,000 neutrinos they studied at the South Pole. Their paper (published in Nature Physics) is one step down a road that they hope will lead to quantum gravity. This hypothesized force, if it’s ever demonstrated in real life measurements, could be the physics dongle that adapts general relativity to quantum mechanics at last.

Keep reading