Category: quantum physics – Page 508
Ars Technica’s Chris Lee has spent a good portion of his adult life playing with lasers, so he’s a big fan of photon-based quantum computing. Even as various forms of physical hardware like superconducting wires and trapped ions made progress, it was possible to find him gushing about an optical quantum computer put together by a Canadian startup called Xanadu. But, in the year since Xanadu described its hardware, companies using that other technology continued to make progress by cutting down error rates, exploring new technologies, and upping the qubit count.
But the advantage of optical quantum computing didn’t go away, and now Xanadu is back with a reminder that it still hasn’t gone away. Thanks to some tweaks to the design it described a year ago, Xanadu is now able to sometimes perform operations with more than 200 qubits. And it has shown that simulating the behavior of just one of those operations on a supercomputer would take 9,000 years, while its optical quantum computer can do them in just a few-dozen milliseconds.
This is an entirely contrived benchmark: Just as Google’s quantum computer did, the quantum computer is just being itself while the supercomputer is trying to simulate it. The news here is more about the potential of Xanadu’s hardware to scale.
Circa 2019
Robust quantum energy storage devices are essential to realize powerful next-generation batteries. Herein, we provide a proof of concept for a loss-free excitonic quantum battery (EQB) by using an open quantum network model that exhibits exchange symmetries linked to its structural topology. By storing electronic excitation energy in a symmetry-protected dark state living in a decoherence-free subspace, one can protect the charged EQB from environment-induced energy losses, thereby making it a promising platform for long-term energy storage. To illustrate the key physical principles and potential functionality of this concept, we consider an open quantum network model of a para-benzene-like structure.
Physicists have just taken an amazing step towards quantum devices that sound like something out of science fiction.
For the first time, isolated groups of particles behaving like bizarre states of matter known as time crystals have been linked into a single, evolving system that could be incredibly useful in quantum computing.
Following the first observation of the interaction between two time crystals, detailed in a paper two years ago, this is the next step towards potentially harnessing time crystals for practical purposes, such as quantum information processing.
As physicists delve deeper into the quantum realm, they are discovering an infinitesimally small world composed of a strange and surprising array of links, knots and winding. Some quantum materials exhibit magnetic whirls called skyrmions—unique configurations described as “subatomic hurricanes.” Others host a form of superconductivity that twists into vortices.
Now, in an article published in Nature a Princeton-led team of physicists has discovered that electrons in quantum matter can link to one another in strange new ways. The work brings together ideas in three areas of science—condensed matter physics, topology, and knot theory —in a new way, raising unexpected questions about the quantum properties of electronic systems.
Topology is the branch of theoretical mathematics that studies geometric properties that can be deformed but not intrinsically changed. Topological quantum states first came to the public’s attention in 2016 when three scientists, including Duncan Haldane, who is Princeton’s Thomas D. Jones Professor of Mathematical Physics and Sherman Fairchild University Professor of Physics, were awarded the Nobel Prize for their theoretical prediction of topology in electronic materials.
A computer capable of achieving quantum advantage – a demonstration of supremacy over conventional machines – is the first that anyone can use over the internet.
When it is free in cold space, a molecule will spontaneously cool down by slowing its rotation and losing rotational energy in quantum transitions. Physicists have shown that this rotational cooling process can be accelerated, slowed down and even inverted by the molecule’s collisions with surrounding particles.
Researchers at the Max-Planck Institute for Nuclear Physics in Germany and the Columbia Astrophysics Laboratory have recently carried out an experiment aimed at measuring the rate of quantum transitions caused by collisions between molecules and electrons. Their findings, published in Physical Review Letters, offer the first experimental evidence of this rate, which had previously only been theoretically estimated.
“When electrons and molecular ions are present in tenuous, ionized gases, the lowest quantum level populations of the molecules can be changed in a collision process,” Ábel Kálosi, one of the researchers who carried out the study, told Phys.org. “One example of this process is in interstellar clouds, where observations reveal molecules predominantly in their lowest quantum states. The attractive force between the negatively charged electrons and the positively charged molecular ions makes the process of electronic collisions particularly efficient.”
For the first ever time, MIT scientists have quantified the temporal coherence (lifetime) of graphene qubits-meaning to what extent it can keep up a special state that enables it to speak to two coherent states at the same time.
As of late, specialists have been incorporating graphene-based materials into superconducting quantum computing gadgets, which guarantee quicker, progressively proficient computing, among different advantages. Up to this point, be that as it may, there’s been no recorded coherence for these advanced qubits, so there’s no knowing whether they’re feasible for practical quantum computing.
In a new study, scientists demonstrated a coherent qubit made from graphene and exotic materials. These materials empower the qubit to change states through voltage, much like transistors in today’s traditional computer chips — and not at all like most different kinds of superconducting qubits. Also, the specialists put a number to that coherence, timing it at 55 nanoseconds, before the qubit comes back to its ground state.
The king is dead, long live the king… of supercomputers!
In this video I discuss New Fastest Supercomputer in the World and the first official Exascale supercomputer — Frontier Supercomputer located at Oak Ridge Lab.
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