Rice University physicist Qimiao Si began mapping quantum criticality more than a decade ago, and he’s finally found a traveler that can traverse the final frontier.
The traveler is an alloy of cerium palladium and aluminum, and its journey is described in a study published online this week in Nature Physics by Si, a theoretical physicist and director of the Rice Center for Quantum Materials (RCQM), and colleagues in China, Germany and Japan.
Si’s map is a graph called a phase diagram, a tool that condensed-matter physicists often use to interpret what happens when a material changes phase, as when a solid block of ice melts into liquid water.
The quantum superposition principle has been tested on a scale as never before in a new study by scientists at the University of Vienna in collaboration with the University of Basel. Hot, complex molecules composed of nearly two thousand atoms were brought into a quantum superposition and made to interfere. By confirming this phenomenon – “the heart of quantum mechanics”, in Richard Feynman’s words – on a new mass scale, improved constraints on alternative theories to quantum mechanics have been placed. The work was published in Nature Physics on September 23, 2019.
Quantum to classical?
The superposition principle is a hallmark of quantum theory which emerges from one of the most fundamental equations of quantum mechanics, the Schrödinger equation. It describes particles in the framework of wave functions, which, much like water waves on the surface of a pond, can exhibit interference effects. But in contrast to water waves, which are a collective behavior of many interacting water molecules, quantum waves can also be associated with isolated single particles.
For the first time, physicists in the US have confirmed a decades-old theory regarding the breaking of time-reversal symmetry in gauge fields. Marin Soljacic at the Massachusetts Institute of Technology and an international team of researchers have made this first demonstration of the “non-Abelian Aharonov-Bohm effect” in two optics experiments. With improvements, their techniques could find use in optoelectronics and fault-tolerant quantum computers.
First emerging in Maxwell’s famous equations for classical electrodynamics, a gauge theory is a description of the physics of fields. Gauge theories have since become an important part of physicists’ descriptions of the dynamics of elementary particles – notably the theory of quantum electrodynamics.
A salient feature of a gauge theory is that the physics it describes does not change when certain transformations are made to the underlying equations describing the system. An example is the addition of a constant scalar potential or a “curl-free” vector potential to Maxwell’s equations. Mathematically, this does not change the electric and magnetic fields that act on a charged particle such as an electron – and therefore the behaviour of the electron – so Maxwell’s theory is gauge invariant.
This thorough review focuses on the impact of AI, 5G, and edge computing on the healthcare sector in the 2020s as well as a look at quantum computing’s potential impact on AI, healthcare, and financial services.
In years to come, quantum computers and quantum networks might be able to tackle tasks that are inaccessible to traditional computer systems. For instance, they could be used to simulate complex matter or enable fundamentally secure communications.
The elementary building blocks of quantum information systems are known as qubits. For quantum technology to become a tangible reality, researchers will need to identify strategies to control many qubits with very high precision rates.
Theory suggests that empty space is filled with enormous energy, but according to a new proposal this energy may be hidden because its effects cancel at the tiniest scales.
Quantum computers exist today, although they’re limited, cut-down versions of what we hope fully blown quantum computers are going to be able to do in the future.
But now, researchers have developed hardware for a ‘probabilistic computer’ – a device that might be able to bridge the gap between genuine quantum computers and the standard PCs and Macs we have today.
The special trick that a probabilistic computer can do is to solve quantum problems without actually going quantum, as it were. It does this using a p-bit, which the team behind this research describes as a “poor man’s qubit”.
Research Triangle Park, N.C. — A U.S. Army research result brings the quantum internet a step closer. Such an internet could offer the military security, sensing, and timekeeping capabilities not possible with traditional networking approaches.
The U.S. Army’s Combat Capability Development’s Army Research Laboratory’s Center for Distributed Quantum Information, funded and managed by the lab’s Army Research Office, saw researchers at the University of Innsbruck achieve a record for the transfer of quantum entanglement between matter and light — a distance of 50 kilometers using fiber optic cables.
Entanglement is a correlation that can be created between quantum entities such as qubits. When two qubits are entangled and a measurement is made on one, it will affect the outcome of a measurement made on the other, even if that second qubit is physically far away.
Leonard Susskind is a professor of theoretical physics at Stanford University, and founding director of the Stanford Institute for Theoretical Physics. He is widely regarded as one of the fathers of string theory and in general as one of the greatest physicists of our time both as a researcher and an educator. This conversation is part of the Artificial Intelligence podcast.
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OUTLINE: 00:00 — Introduction 01:02 — Richard Feynman 02:09 — Visualization and intuition 06:45 — Ego in Science 09:27 — Academia 11:18 — Developing ideas 12:12 — Quantum computers 21:37 — Universe as an information processing system. 26:35 — Machine learning 29:47 — Predicting the future 30:48 — String theory 37:03 — Free will 39:26 — Arrow of time 46:39 — Universe as a computer 49:45 — Big bang 50:50 — Infinity 51:35 — First image of a black hole 54:08 — Questions within the reach of science. 55:55 — Questions out of reach of science.
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A U.S. Army research result brings the quantum internet a step closer. Such an internet could offer the military security, sensing and timekeeping capabilities not possible with traditional networking approaches.
The U.S. Army’s Combat Capability Development’s Army Research Laboratory’s Center for Distributed Quantum Information, funded and managed by the lab’s Army Research Office, saw researchers at the University of Innsbruck achieve a record for the transfer of quantum entanglement between matter and light—a distance of 50 kilometers using fiber optic cables.
Entanglement is a correlation that can be created between quantum entities such as qubits. When two qubits are entangled and a measurement is made on one, it will affect the outcome of a measurement made on the other, even if that second qubit is physically far away.
