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Archive for the ‘quantum physics’ category: Page 399

Mar 19, 2020

The imitation game: Scientists describe and emulate new quantum state of entangled photons

Posted by in categories: computing, engineering, information science, nanotechnology, quantum physics

:oooo.


A research team from ITMO University, with the help of colleagues from MIPT (Russia) and Politecnico di Torino (Italy), has predicted a novel type of topological quantum state of two photons. Scientists have also applied a new, affordable experimental method for testing this prediction. The method relies on an analogy: Instead of expensive experiments with quantum systems of two or more entangled photons, the researchers have used resonant electric circuits of higher dimensionality described by similar equations. The obtained results can be useful for the engineering of optical chips and quantum computers without the need for expensive experiments. The research was published in Nature Communications.

Light plays a key role in modern information technologies: With its help, information is transmitted over large distances via optical fibers. In the future, scientists anticipate the invention of optical chips and computers that process information with the help of photons—light quanta—instead of electrons, as it is done today. This will decrease energy consumption, while also increasing the capabilities of computers. However, to turn these predictions into reality, fundamental and applied research of light behavior at the micro- and nanoscale is needed.

Continue reading “The imitation game: Scientists describe and emulate new quantum state of entangled photons” »

Mar 19, 2020

2,000 Atoms Exist in Two Places at Once in Unprecedented Quantum Experiment

Posted by in categories: particle physics, quantum physics

:oooo.


The new experiment demonstrated a bizarre quantum effect from the double-slit experiment at an unprecedented scale.

Mar 19, 2020

Model simulator helps researchers map complex physics phenomena

Posted by in categories: particle physics, quantum physics

To understand the behavior of quantum particles, imagine a pinball game—but rather than one metal ball, there are billions or more, all ricocheting off each other and their surroundings.

Physicists have long tried to study this interactive system of strongly correlated particles, which could help illuminate elusive phenomena like and magnetism.

One classic method is to create a simplified model that can capture the essence of these particle interactions. In 1963, physicists Martin Gutzwiller, Junjiro Kanamori and John Hubbard—working separately—proposed what came to be called the Hubbard model, which describes the essential physics of many interacting quantum particles. The solution to the model, however, only exists in one dimension. For decades, physicists have tried to realize the Hubbard model in two or three dimensions by creating that can mimic it.

Mar 18, 2020

Russia’s Kilo-Class Submarines: “Black Holes” No Navy Wants to Fight

Posted by in categories: cosmology, particle physics, quantum physics

I think these can be fought with current technology such as quantum radar even other higher level technology. It can also be hacked with quantum radar or neutrino beams.


Know colloquially as the “Black Holes” by the U.S. Navy, the Improved-Kilo-class of submarines are quite deadly — and could turn the balance of power in the South China Sea in China’s favor.

Mar 18, 2020

Russian Scientists Break Google’s Quantum Algorithm

Posted by in categories: cybercrime/malcode, information science, quantum physics

Clause density is something new to me but seems interesting as I know shores algorithm is the only thing that can hack systems.


Google is racing to develop quantum-enhanced processors that utilize quantum mechanical effects to one day dramatically increase the speed at which data can be processed.

In the near term, Google has devised new quantum-enhanced algorithms that operate in the presence of realistic noise. The so-called quantum approximate optimization algorithm, or QAOA for short, is the cornerstone of a modern drive towards noise-tolerant quantum-enhanced algorithm development.

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Mar 18, 2020

Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2

Posted by in categories: materials, quantum physics

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The quantum spin Hall insulator is characterized by a bandgap in the two-dimensional (2D) interior and helical 1D edge states1,2,3. Inducing superconductivity in the helical edge state results in a 1D topological superconductor, a highly sought-after state of matter at the core of many proposals for topological quantum computing4. In the present study, we report the coexistence of superconductivity and the quantum spin Hall edge state in a van der Waals heterostructure, by placing a monolayer of 1T′-WTe2, a quantum spin Hall insulator1,2,3, on a van der Waals superconductor, NbSe2. Using scanning tunnelling microscopy and spectroscopy (STM/STS), we demonstrate that the WTe2 monolayer exhibits a proximity-induced superconducting gap due to the underlying superconductor and that the spectroscopic features of the quantum spin Hall edge state remain intact. Taken together, these observations provide conclusive evidence for proximity-induced superconductivity in the quantum spin Hall edge state in WTe2, a crucial step towards realizing 1D topological superconductivity and Majorana bound states in this van der Waals material platform.

Mar 17, 2020

Researchers set benchmark to determine achievement of quantum computing

Posted by in categories: chemistry, quantum physics, supercomputing

The race toward the first practical quantum computer is in full stride. Companies, countries, collaborators, and competitors worldwide are vying for quantum supremacy. Google says it’s already there. But what does that mean? How will the world know when it’s been achieved?

Using , at PNNL have set a mark that a quantum system would need to surpass to establish quantum supremacy in the realm of chemistry.

That’s because the fastest classical computers available today are getting better and better at simulating what a quantum computer will eventually be expected to do. To prove itself in the real world, a quantum computer will need to be able to outdo what a fast supercomputer can do. And that’s where the PNNL-led team have set a benchmark for quantum computers to beat.

Mar 17, 2020

Time crystals enter the real world of condensed matter

Posted by in category: quantum physics

Can we realize non-trivial condensed-matter phases – such as topological insulating phases – in the time dimension? Topological insulators are condensed-matter systems that are insulators in their interior but, by virtue of the topological properties of the electronic structure, have conducting surface (edge) states. They are characterized by global topological invariants. An example of a topological invariant is the number of holes a surface has: a sphere has no holes while a torus has one. It is hard to change such a topological invariant because it is not possible to gradually introduce a hole in a sphere in order to change it to a torus – either there is a hole or there is no hole, but there is nothing like a fraction of a hole. Even the vacuum (empty space) has trivial topological invariants. In order to reconcile a change of this invariant at the interface between the vacuum and a topological insulator, there are surface (edge) states that close the gap between the energy bands of the insulator, thereby producing conducting behaviour.

Can a quantum swing behave like an electron in a topological insulator? Yes, for example if we ask the child to push with a combination of a resonant frequency ω and a sub-harmonic frequency ω /2 (Optica 5 1390, New J. Phys. 21 052003). Then the motion of the swing effectively creates a chain of lattice sites along the resonant orbit with staggered hopping amplitudes, and thus reproduces an example of a topological system, called the Su–Schrieffer–Heeger lattice. In order to observe the edge states, we need to create an “edge” in the motion of the swing and then check if there are quantum states that are localized close to it. How can we create an edge in time? We ask the child to jump on the swing from time to time, which introduces a barrier in the chain of lattice sites along the resonant orbit and consequently breaks the time-translational symmetry along the orbit, similar to how a surface breaks spatial-translational symmetry in an ordinary topological insulator.

Mar 15, 2020

A new quantum theory predicts that the future could be influencing the past

Posted by in categories: futurism, quantum physics

💫🧘‍♀️💫


A new study challenges what we understand about the workings of time.

Mar 13, 2020

Initialization of quantum simulators

Posted by in categories: biological, particle physics, quantum physics

Simulating computationally complex many-body problems on a quantum simulator has great potential to deliver insights into physical, chemical and biological systems. Physicists had previously implemented Hamiltonian dynamics but the problem of initiating quantum simulators to a suitable quantum state remains unsolved. In a new report on Science Advances, Meghana Raghunandan and a research team at the institute for theoretical physics, QUEST institute and the Institute for quantum optics in Germany demonstrated a new approach. While the initialization protocol developed in the work was largely independent of the physical realization of the simulation device, the team provided an example of implementing a trapped ion quantum simulator.

Quantum simulation is an emergent technology aimed at solving important open problems relative to high-temperature superconductivity, interacting quantum field theories or many-body localization. A series of experiments have already demonstrated the successful implementation of Hamiltonian dynamics within a quantum simulator—however, the approach can become challenging across quantum phase transitions. In the new strategy, Raghunandan et al. overcame this problem by building on recent advances in the use of dissipative quantum systems to engineer interesting many-body states.

Almost all many-body Hamiltonians of interest remain outside a previously investigated class and therefore require generalization of the dissipative state preparation procedure. The research team therefore presented a previously unexplored paradigm for the dissipative initialization of a quantum simulator by coupling the many-body system performing the quantum simulation to a dissipatively driven auxiliary particle. They chose the energy splitting within the auxiliary particle to become resonant with the many-body excitation gap of the system of interest; described as the difference of the ground-state energy and the energy of the first excited state. During such conditions of resonance, the energy of the quantum simulator could be transferred efficiently to the auxiliary particle for the former to be cooled sympathetically, i.e., particles of one type, cooled particles of another type.