Quantum

Never-Before-Seen Quantum Hybrid State Discovered on Arsenic Surface.

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MICHELLE STARR

A visualization of the quantum states of electrons on gray arsenic. (Image based on STM data simulations prepared by Shafayat Hossain and the Zahid Hasan group at the Laboratory for Topological Quantum Matter at Princeton University)

Physicists have just found something no one expected, lurking on the surface of an arsenic crystal.

While undertaking a study of quantum topology – the wave-like behavior of particles combined with the mathematics of geometry – a team found a strange hybrid of two quantum states, each describing a different means of current.

“This finding was completely unexpected,” says physicist M. Zahid Hasan of Princeton University. “Nobody predicted it in theory before its observation.”

Topology is becoming increasingly important in understanding the behavior of materials that can only be described by ther wave-like properties, known as quantum matter. Concerned with the geometry of structures that don’t effectively change when bent or warped (but might if they are broken or pierced), topology has the potential to affect the quantum activity of materials in a variety of ways.

A lot of that research involves compounds with a base of bismuth, since bismuth is an efficient topological insulator – a material whose outer layer acts as a conductor of activity, and interior acts as an insulator. That means the electrons inside are immobile, but those on the surface and edges can move around freely.

Commonly used in semiconducting materials, arsenic can also behave as a topological insulator. Physicists, including Hasan and his team, have been looking for new quantum states in topological insulators, particularly those that can operate at room temperature.

Bismuth-based materials have provided many insights, but they require high temperatures and are complicated to synthesize and prepare. Arsenic, by contrast, can be grown in a form that is cleaner than bismuth, and is simpler to prepare. So the researchers grew crystals of gray arsenic, which has a metallic appearance, and applied magnetic fields.

Then, they probed the sample using scanning tunneling microscopy (STM), which produces images at subatomic scales, and photoemission spectroscopy, which measured the energy states of electrons.

They found surface states – electron states that flow along ‘gapless’ surfaces of some kinds of topological insulator – which was fine and normal. But no one expected what else they found – edge states that exist on the boundaries of a completely different kind of topological insulator, and have never before been seen side-by-side with surface states.

“We were surprised,” says physicist Md. Shafayat Hossain of Princeton University. “Gray arsenic was supposed to have only surface states. But when we examined the atomic step edges, we also found beautiful conducting edge modes.”

They could only conclude that what they were observing was a hybrid state that no one has ever seen before.

“Typically, we consider the bulk band structure of a material to fall into one of several distinct topological classes, each tied to a specific type of boundary state,” says physicist David Hsieh of Caltech, who was not involved in the research.

“This work shows that certain materials can simultaneously fall into two classes. Most interestingly, the boundary states emerging from these two topologies can interact and reconstruct into a new quantum state that is more than just a superposition of its parts.”

The discovery could unlock a new kind of quantum materials, which in turn could advance quantum physics research, as well as technologies such as quantum computing.

“We envision that arsenic, with its unique topology, can serve as a new platform at a similar level for developing novel topological materials and quantum devices that are not currently accessible through existing platforms,” Hasan says.

“A new exciting frontier in material science and novel physics awaits!”

Quantum physicists discovered that people have an immortal soul.

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https://www.beautyofplanet.com/quantum-physicists-discovered-that-people-have-an-immortal-soul/?fbclid=IwAR21wO3DuRGQRY1feup8aUTqojyYmi3TVfCJAx6a2uI8ogTdIde2JkJKJFQ

Reality Doesn’t Exist Until We Measure It, Quantum Experiment Confirms.

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Australian scientists have recreated a famous experiment and confirmed quantum physics’s bizarre predictions about the nature of reality, by proving that reality doesn’t actually exist until we measure it – at least, not on the very small scale.

That all sounds a little mind-meltingly complex, but the experiment poses a pretty simple question: if you have an object that can either act like a particle or a wave, at what point does that object ‘decide’?

Our general logic would assume that the object is either wave-like or particle-like by its very nature, and our measurements will have nothing to do with the answer. But quantum theory predicts that the result all depends on how the object is measured at the end of its journey. And that’s exactly what a team from the Australian National University has now found.

“It proves that measurement is everything. At the quantum level, reality does not exist if you are not looking at it,” lead researcher and physicist Andrew Truscott said in a press release.

Known as John Wheeler’s delayed-choice thought experiment, the experiment was first proposed back in 1978 using light beams bounced by mirrors, but back then, the technology needed was pretty much impossible. Now, almost 40 years later, the Australian team has managed to recreate the experiment using helium atoms scattered by laser light.

“Quantum physics predictions about interference seem odd enough when applied to light, which seems more like a wave, but to have done the experiment with atoms, which are complicated things that have mass and interact with electric fields and so on, adds to the weirdness,” said Roman Khakimov, a PhD student who worked on the experiment.

To successfully recreate the experiment, the team trapped a bunch of helium atoms in a suspended state known as a Bose-Einstein condensate, and then ejected them all until there was only a single atom left. 

This chosen atom was then dropped through a pair of laser beams, which made a grating pattern that acted as a crossroads that would scatter the path of the atom, much like a solid grating would scatter light.

They then randomly added a second grating that recombined the paths, but only after the atom had already passed the first grating.

When this second grating was added, it led to constructive or destructive interference, which is what you’d expect if the atom had travelled both paths, like a wave would. But when the second grating was not added, no interference was observed, as if the atom chose only one path.

The fact that this second grating was only added after the atom passed through the first crossroads suggests that the atom hadn’t yet determined its nature before being measured a second time. 

So if you believe that the atom did take a particular path or paths at the first crossroad, this means that a future measurement was affecting the atom’s path, explained Truscott. “The atoms did not travel from A to B. It was only when they were measured at the end of the journey that their wave-like or particle-like behaviour was brought into existence,” he said.

Although this all sounds incredibly weird, it’s actually just a validation for the quantum theory that already governs the world of the very small. Using this theory, we’ve managed to develop things like LEDs, lasers and computer chips, but up until now, it’s been hard to confirm that it actually works with a lovely, pure demonstration such as this one.

Quantum Breakthrough: Unveiling the Mysteries of Electron Tunneling

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New research reveals new insights into electron tunneling dynamics at the sub-nanometer scale. Using a van der Waals complex, Ar-Kr+, and an innovative approach for tracking tunneling dynamics, the research highlights the crucial influence of neighboring atoms in quantum tunneling. This work has important implications for quantum physics, nanoelectronics, and the study of complex biomolecules.

Tunneling is a fundamental process in quantum mechanics, involving the ability of a wave packet to cross an energy barrier that would be impossible to overcome by classical means. At the atomic level, this tunneling phenomenon significantly influences molecular biology. It aids in speeding up enzyme reactions, causes spontaneous DNA mutations, and initiates the sequences of events that lead to the sense of smell.

Photoelectron tunneling is a key process in light-induced chemical reactions, charge and energy transfer, and radiation emission. The size of optoelectronic chips and other devices has been close to the sub-nanometer atomic scale, and the quantum tunneling effects between different channels would be significantly enhanced.

The electronic chip and the Van der Waals complex with an internuclear distance 0.39 nm. Credit: Ming Zhu, Jihong Tong, Xiwang Liu, Weifeng Yang, Xiaochun Gong, Wenyu Jiang, Peifen Lu, Hui Li, Xiaohong Song & Jian Wu

The real-time imaging of electron tunneling dynamics in complex has important scientific significance for promoting the development of tunneling transistors and ultrafast optoelectronic devices. The effect of neighboring atoms on electron tunneling dynamics in the complex is one of the key scientific issues in the fields of quantum physics, quantum chemistry, nanoelectronics, etc.

Recent Research Developments

In a new paper published in Light Science & Application, a team of scientists from Hainan University and East China Normal University designed a van der Waals complex Ar-Kr+ as a prototype system with an internuclear distance of 0.39 nm to track the electron tunneling via the neighboring atom in the system of sub-nanometer scale.

The electron emitted from Ar atom is firstly trapped to the highly excited transient states of the Ar-Kr+* before its eventual release to the continuum. A linearly polarized pump laser pulse is used to prepare the Ar-Kr+ ion by removing e1 from Kr site, and a time-delayed elliptically polarized probe laser pulse is used to track the electron transfer mediated electron tunneling dynamics (e2, orange arrow). Credit: Ming Zhu, Jihong Tong, Xiwang Liu, Weifeng Yang, Xiaochun Gong, Wenyu Jiang, Peifen Lu, Hui Li, Xiaohong Song & Jian Wu

The intrinsic electron localization of the highest occupied molecular orbital of Ar-Kr gives a preference for electron removal from the Kr site in the first ionization step. The site-assisted electron-hole in Ar-Kr+ guarantees that the second electron is mainly removed from the Ar atom in the second ionization step, where the electron may straightly tunnel to the continuum from the Ar atom or alternatively via the neighboring Kr+ ionic core.

In combination with the improved Coulomb-corrected strong-field approximation (ICCSFA) method developed by the team, which is able to take into account the Coulomb interaction under the potential during tunneling, and by monitoring the photoelectron transverse momentum distribution to track the tunneling dynamics, then, it was discovered that there are two effects of strong capture and weak capture of tunneling electrons by a neighboring atom.

This work successfully reveals the critical role of neighboring atoms in electron tunneling in sub-nanometer complex systems. This discovery provides a new way to deeply understand the key role of the Coulomb effect under the potential barrier in the electron tunneling dynamics, solid high harmonics generation, and lays a solid research foundation for probing and controlling the tunneling dynamics of complex biomolecules.

Superconducting quantum bits with artificial damping tackle the many body problem

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Circuit QED represents one of the most advanced architectures in the race for a quantum computer. Its elementary building blocks, the superconducting quantum bits and microwave cavities, play the role of nearly ideal spins and springs. Thanks to technological progress, the spin/spring coupling constant greatly exceeds the decoherence rate of the system, so that spins and springs get strongly quantum-entangled. This strong coupling regime is exploited by numerous teams to perform quantum algorithms with a growing number of quantum bits.1 In this context, dissipation sources, which cause decoherence, appear as the physicist enemy number one, which limits the size of quantum computers and their performances. A lot of efforts is devoted to the development of quantum error correction codes which fight the destruction of quantum information.2 This requires to increase the number of physical bits used to encode one bit of information, making the realization of complex quantum algorithms even more challenging.

However, a weakness can sometimes be turned into a strength. Indeed, superconducting circuits can also be used to perform a direct simulation of intrinsically dissipative quantum systems, in principle. In this case, decoherence in the circuit must mimic the one in the real system, and it thus turns from a spurious effect to a key ingredient. For example, one can imagine to emulate in a controlled way the Kondo effect, which epitomizes many body condensed matter problems. This effect, which was discovered in the 30’s, consists in a low temperature increase of the resistance of some metals, due to the spin-flip scattering of their continuum of itinerant electrons on magnetic impurities.3 The Kondo model is also central to understand strongly correlated electron behavior in quantum dot circuits, heavy-fermion materials and high-temperature superconductors.4 It is possible to make an exact theoretical description of the Kondo effect in some limiting cases like the high or low temperature regimes, but the general case remains challenging. Theorists expect the formation of an intriguing Kondo cloud of itinerant electrons, with a spin entangled with impurity spins, but this feature could not be observed directly so far.5

Recently, it has been suggested to simulate Kondo physics with photons by using a superconducting quantum bit coupled to two semi-infinite microwave transmission lines.6,7 This physical situation corresponds to a dissipative spin/boson model, where dissipation is provided by the transmission lines due to their continuous density of photonic modes. Kondo physics is expected because there exists a direct mapping between the dissipative spin/boson model and the Kondo model.8 Nevertheless, this geometry cannot fully exploit the power of Circuit QED. Indeed, microwave resonant techniques, which enable an efficient control and monitoring of quantum bits, cannot be used to reveal directly the phenomena which occur inside a photonic continuum. Yet…it is possible to sit on the fence by using a very long but finite waveguide. In this case, the waveguide forms a cavity with a discrete spectrum, but the round-trip of photons in this cavity is much longer than the qubit/cavity mode coupling constant, so that the qubit effectively feels an “artificial” dissipative environment, at least for times shorter than the photonic round trip. If, on top of that, the qubit/cavity coupling is stronger than the energy spacing between the photonic modes, and the qubit nonlinearity sufficiently large, many-body physics is expected. Strinkingly, in this geometry, the many modes of the effective bath could be addressed individually thanks to microwave resonant techniques. One can thus dream of measuring directly the Kondo cloud, or even its formation and dynamics in quench experiments where the system would be brought suddenly into the Kondo regime.

Motivated by these perspectives, several teams have revisited experimentally the problem of a superconducting qubit coupled to a long microwave coplanar waveguide.9,10 Now, these experiments are brought to the next technical level by two groups who use arrays of Josephson junctions12 or squids11 as a waveguide. These arrays have a high impedance that favors strong qubit/bath couplings. Furthermore, in ref. 11, the squid array architecture enables a strong tunability of the bath modes with the magnetic field, which could be instrumental to study the parametric dependences in a many-body problem. Puertas-Martínez and coworkers11 perform an impressively accurate parameter-free modeling of their experiment, which reveals the breakdown of the rotating wave approximation, expected in the multimode strong coupling regime. Kuzmin and colleagues12 obtain an even larger qubit/bath coupling, so that individual anticrossings between the qubit and the numerous bath modes cannot be distinguished anymore due to the complete dissolution of the qubit state in these modes. In both experiments, the bath levels are resolved and studied individually. In order to enter the deep many-body regime, further experimental efforts are necessary to increase the qubit nonlinearity. However, considering the rapid experimental progress, one can hope the simulation of many-body physics with superconducting circuits to be within reach soon.

Quantum Engineer Talks Untapped Potential of Human Mind, Major Problems in Science Today

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Right: Dr. Garret Moddel (Courtesy of Dr. Garret Moddel) Background: (Flowgraph/iStock)

In Beyond Science, Epoch Times explores research and accounts related to phenomena and theories that challenge our current knowledge. We delve into ideas that stimulate the imagination and open up new possibilities. Share your thoughts with us on these sometimes controversial topics in the comments section below.

Dr. Garret Moddel teaches a course at the University of Colorado that explores psychic phenomena, such as remote viewing. Preliminary studies in his classroom have even seemed to suggest that students can accurately predict stock market changes!

His students have told him that the course has opened their minds, but not just in terms of becoming aware of psi phenomena (Psi refers to any psychic phenomenon, such as psychokinesis, telepathy, or clairvoyance). Perhaps more importantly, Dr. Moddel has taught them how science works, and how to think more critically about science.

Science by Consensus Is a Problem

If 97 percent of scientists say something is true, does that make it true? A large portion of the general public may think so. But, Dr. Moddel said, “That’s not the way that science works. It’s not a consensus sport. In fact, it’s often the lone mavericks who, in the end of it, are right.”

If 97 percent of scientists say something is true, does that make it true?

“We know based on historical examples that most of the science that we now believe is going to be modified, so nothing that we have is really cast in stone,” he said. “Scientific progress is slowed by cascading opinions.”

He watched a classic example of this take hold of his mother’s life. In the 1950s, nutritionist Ancel Keys conducted what is now known as the “Seven Countries Study,” commissioned by the U.S. Public Health Service. Keys found that countries with less dietary fat had healthier populations. “He was very influential, and once he stated that opinion, it stuck,” Dr. Moddel said.

For the past 50 years, the United States has been operating on this belief, with manufacturers cutting fat in foods, but sometimes adding sugar and other unhealthy elements to compensate for lost flavor. Though many studies after Keys’ showed his conclusions to be incorrect, it’s only in the past five years that the scientific community has really begun to recognize that sugar, not fat, is the enemy.

Dr. Moddel’s mother made great efforts as she got older and continually gained weight to cut fat from her diet. He blames this cascading effect. He said the incorrect conclusion, perpetuated in spite of much evidence to the contrary, has probably cost many people their lives.

While many scientists who go against the grain are cut down by their colleagues, tenure thankfully allows many of today’s mavericks—including Dr. Moddel—to study psi and other not-quite-popular topics without professional repercussions.

His more mainstream work, in quantum engineering, has earned Dr. Moddel a position of respect in the scientific community. His conventionally minded colleagues are “respectful, at least on the surface” of his psi work, Dr. Moddel said. The university, after making him jump through some hoops to establish his psi-studies course as a critical-thinking course, now treats him with “benign neglect,” he said.

Though the security of tenure is far out of reach for Dr. Moddel’s students, some of them are eager to jump right into psi studies. “I’m the one who injects caution,” he said. He tells them, “You’ve got a career to think about. Yes, please look into this, but in order not to sabotage yourself, make sure you do really good mainstream work.”

Remote Viewing in Dr. Moddel’s Classroom

The United States government declassified documents in the 1990s showing it has extensively studied and used remote viewing. Dr. Moddel has brought Paul Smith, a U.S. Army-trained remote viewing researcher, into the class to help his students.

Dr. Moddel gave an example of a student project. The student wanted to see what would happen if he removed one of the two people involved in remote viewing and replaced the human with a machine. In remote viewing experiments, a person is usually asked to draw whatever image comes to mind. Two images have been preselected by those conducting the experiment, each corresponding to an event in the future.

For example, the image of a bowling ball could be designated as meaning the value of a particular stock will rise the following day. The image of a rabbit means the value of that stock will fall the following day.

So one person, unaware of which images have been chosen, draws an image that randomly comes to mind. The other person involved in the experiment is the judge. The judge looks at the picture the person has drawn and decides if it looks more like a bowling ball or a rabbit. If the images drawn seem to consistently correspond to the actual stock market outcomes of the following day, it would seem the person who drew the pictures is the one performing remote viewing. But, Dr. Moddel reminds us, the judge could also be exercising some psi ability.

Instead of having a person draw the images, the student had a machine do so. He used a random number generator (a machine designed to randomly create bits) to output the bit stream to a computer, which used the stream to form an image. The random number generator was situated next to a person who served as the viewer, and presumably the random number generator output was being influenced by the viewer.

Even with the machine, the student got some statistically significant results. In previous experiments, Dr. Moddel’s students have been able to predict changes in the stock market at a rate above chance (correctly seven times in seven attempts).

 Dr. Moddel’s students have been able to predict changes in the stock market at a rate above chance (correctly seven times in seven attempts).
He and fellow researchers are currently engaged in a crowdfunding campaign to further investigate this. He has talked before about the importance of intention in psi experiments—it’s been suggested by other experiments in his classroom that the enthusiasm or belief in psi of the subjects or the experimenters can affect the results—so we wondered what role intention might play in a stock market experiment