Researchers in China are using drones as nodes in the development of an airborne quantum communications network. The article describes how such a network, using a quantum drone would be nigh unhackable.
Category: quantum physics – Page 782
New theory for trapping light particles aims to advance development of quantum computers
If we could trap light it could be used as a force field or even a lightsaber in future developments :3.
Quantum computers, which use light particles (photons) instead of electrons to transmit and process data, hold the promise of a new era of research in which the time needed to realize lifesaving drugs and new technologies will be significantly shortened. Photons are promising candidates for quantum computation because they can propagate across long distances without losing information, but when they are stored in matter they become fragile and susceptible to decoherence. Now researchers with the Photonics Initiative at the Advanced Science Research Center (ASRC) at The Graduate Center, CUNY have developed a new protocol for storing and releasing a single photon in an embedded eigenstate—a quantum state that is virtually unaffected by loss and decoherence. The novel protocol, detailed in the current issue of Optica, aims to advance the development of quantum computers.
“The goal is to store and release single photons on demand by simultaneously ensuring the stability of data,” said Andrea Alù, founding director of the ASRC Photonics Initiative and Einstein Professor of Physics at The Graduate Center. “Our work demonstrates that is possible to confine and preserve a single photon in an open cavity and have it remain there until it’s prompted by another photon to continue propagating.”
The research team used quantum electrodynamics techniques to develop their theory. They investigate a system composed of an atom and a cavity—the latter of which is partially open and therefore would normally allow light trapped in the system to leak out and be quickly lost. The research team showed, however, that under certain conditions destructive interference phenomena can prevent leakage and allow a single photon to be hosted in the system indefinitely. This embedded eigenstate could be very helpful for storing information without degradation, but the closed nature of this protected state also creates a barrier to exterior stimuli, so that single photons also cannot be injected into the system. The research team was able to overcome this limitation by exciting the system at the same time with two or more photons.
Interaction-induced topology in symmetry-broken phase
Symmetry is a fundamental characteristic in nature. Understanding the mechanisms that break symmetries is essential to scientific research. Spontaneous symmetry breaking (SSB), in particular, occurs when thermal or quantum fluctuations drive a system from a symmetric state into an ordered state, as it occurs when a liquid turns into a solid. This mechanism allows researchers to classify different phases of matter according to the different patterns generated by the broken symmetry.
In the last decades, topology has also been recognized as a crucial characteristic to describe how matter is organized at the fundamental level. In this case, it is no longer the breaking of certain symmetries, but their conservation, which gives rise to novel states of matter, the so-called symmetry-protected topological (SPT) phases. Different topological phases might present the same symmetries, but they can be distinguished by a global topological invariant, which takes integer values and is preserved under continuous deformations.
Current research in condensed matter physics aims to understand how symmetry breaking and symmetry protection compete, in particular in the presence of interactions. In a recent paper published in Nature Communications, ICFO researchers Daniel Gonzalez and Przemyslaw Grzybowski, led by Alexandre Dauphin and ICREA Prof. at ICFO Maciej Lewenstein, in collaboration with Alejandro Bermudez from the Universidad Complutense in Madrid, report how these two processes cooperate, giving rise to new strongly-correlated topological effects.
Automatic Quantum Computer Programming: A Genetic Programming Approach
Provides an introduction to quantum computing for non-physicists, as well as an introduction to genetic programming for non-computer-scientists. The book explores several ways in which genetic programming can support automatic quantum computer programming and presents detailed descriptions of specific techniques, along with several examples of their human-competitive performance on specific problems. Source code for the author’s QGAME quantum computer simulator is included as an appendix, and pointers to additional online resources furnish the reader with an array of tools for automatic quantum computer programming.
Researchers demonstrate new path to reliable quantum computation
Researchers at the University of Chicago published a novel technique for improving the reliability of quantum computers by accessing higher energy levels than traditionally considered. Most prior work in quantum computation deals with “qubits,” the quantum analogue of binary bits that encode either zero or one. The new work instead leverages “qutrits,” quantum analogues of three-level trits capable of representing zero, one or two.
The UChicago group worked alongside researchers based at Duke University. Both groups are part of the EPiQC (Enabling Practical-scale Quantum Computation) collaboration, an NSF Expedition in Computing. EPiQC’s interdisciplinary research spans from algorithm and software development to architecture and hardware design, with the ultimate goal of more quickly realizing the enormous potential of quantum computing for scientific discovery and computing innovation.
