Lifeboat Foundation

Opening new possibilities for quantum sensors, atomic clocks and tests of fundamental physics, JILA researchers have developed new ways of “entangling” or interlinking the properties of large numbers of particles. In the process they have devised ways to measure large groups of atoms more accurately even in disruptive, noisy environments.

The new techniques are described in a pair of papers published in Nature. JILA is a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.

“Entanglement is the holy grail of measurement science,” said Ana Maria Rey, a theoretical physicist and a JILA and NIST Fellow. “Atoms are the best sensors ever. They’re universal. The problem is that they’re quantum objects, so they’re intrinsically noisy. When you measure them, sometimes they’re in one energy state, sometimes they’re in another state. When you entangle them, you can manage to cancel the noise.”

The team achieved 99.99 percent accuracy with a single-qubit gate and 99.9 percent accuracy with a two-qubit gate.

Researchers at the Massachusetts Institute of Technology (MIT) have developed a new circuit that can do quantum computation with a high degree of accuracy. The researchers used a new type of superconducting qubit called the fluxonium, a press release said.

Quantum computers are considered the next frontier of computing since they can perform calculations at speeds that are decades ahead of supercomputers being used today. The flip side of such high speeds is that they can accumulate errors equally fast.

Black holes may be less unique than previously thought, as the expansion due to a cosmological constant can hold apart a pair of holes and allow them to mimic a single black hole.

Black holes are astonishing objects that can pack the mass of Earth into a space the size of a pea. A remarkable attribute is their stunning simplicity, which is encapsulated in the celebrated uniqueness theorems [1]. Briefly stated, these theorems say that there is only one solution to Einstein’s equations of general relativity for a fully collapsed (nonevolving) system having fixed mass and angular momentum [2]. The implication is that all black holes that have settled down to equilibrium with the same mass and rotation are precisely the same: their entire behavior described by a single equation—the so-called Kerr solution—filling only a few lines of paper!

But there is a catch. The uniqueness theorems make a number of assumptions, the key one being that the space around the black hole is “empty”—in other words, there is no energy that might influence the black hole. Such energy can arise from fields, for example, those of the standard model, or from a “cosmological constant,” which is a form of dark energy that might be behind the accelerated expansion of our Universe today. In a fascinating study, Óscar Dias from the University of Southampton, UK, and colleagues demonstrate that uniqueness is violated in the presence of a positive cosmological constant [3]. Specifically, they show that a pair of black holes whose mutual attraction is balanced by the cosmic expansion would look the same to a distant observer as a single isolated black hole. The results may lead to a rethinking of how simple black holes really are.

Synthetic fertilizers, one the most important developments in modern agriculture, have enabled many countries to secure a stable food supply. Among them, organic ureas (or organoureas) have become prominent sources of nitrogen for crops. Since these compounds do not dissolve immediately in water, but instead are slowly decomposed by soil microorganisms, they provide a stable and controlled supply of nitrogen, which is crucial for plant growth and function.

However, traditional methods to synthesize organoureas are environmentally harmful due to their use of toxic substances, such as phosgene. Although alternative synthesis strategies have been demonstrated, these either rely on expensive and scarce noble metals or employ catalysts that cannot be reused easily.

In a recent effort to address these challenges, a research team including Honorary Professor Hideo Hosono from Tokyo Institute of Technology, Japan, has leveraged the quantum properties of bismuth selenide (Bi₂Se₃) to synthesize organoureas. Their study is published in Science Advances.

For years, researchers have tried various ways to coax quantum bits — or qubits, the basic building blocks of quantum computers — to remain in their quantum state for ever-longer times, a key step in creating devices like quantum sensors, gyroscopes, and memories.

A team of physicists from MIT

MIT is an acronym for the Massachusetts Institute of Technology. It is a prestigious private research university in Cambridge, Massachusetts that was founded in 1861. It is organized into five Schools: architecture and planning; engineering; humanities, arts, and social sciences; management; and science. MIT’s impact includes many scientific breakthroughs and technological advances. Their stated goal is to make a better world through education, research, and innovation.

Researchers from the University of Science and Technology of China(USTC) of the Chinese Academy of Sciences (CAS) have developed an ultra-cold atom quantum simulator to study the relationship between the non-equilibrium thermalization process and quantum criticality in lattice gauge field theories. The research was led by Pan Jianwei and Yuan Zhensheng, in collaboration with Zhai Hui from Tsinghua University and Yao Zhiyuan from Lanzhou University.

Their findings reveal that multi-body systems possessing gauge symmetry tend to thermalize to an equilibrium state more easily when situated in a quantum phase transition critical region. The results were published in Physical Review Letters.

Gauge theory and statistical mechanics are two foundational theories of physics. From the Maxwell’s equations of classical electromagnetism to quantum electrodynamics and the Standard Model, which describe the interactions of fundamental particles, all adhere to specific gauge symmetries. On the other hand, statistical mechanics connects the microscopic states of large ensembles of particles (such as atoms and molecules) to their macroscopic statistical behaviors, based on the principle of maximum entropy proposed by Boltzmann and others. It elucidates, for instance, how the energy distribution of microscopic particles affects macroscopic quantities like pressure, volume, or temperature.

The newly upgraded Linac Coherent Light Source (LCLS) X-ray free-electron laser (XFEL) at the Department of Energy’s SLAC National Accelerator Laboratory successfully produced its first X-rays, and researchers around the world are already lined up to kick off an ambitious science program.

The upgrade, called LCLS-II, creates unparalleled capabilities that will usher in a new era in research with X-rays.

Scientists will be able to examine the details of quantum materials with unprecedented resolution to drive new forms of computing and communications; reveal unpredictable and fleeting chemical events to teach us how to create more sustainable industries and clean energy technologies; study how biological molecules carry out life’s functions to develop new types of pharmaceuticals; and study the world on the fastest timescales to open up entirely new fields of scientific investigation.

Under the limitation of current density, micro-LED is difficult to achieve watts level optical power, which is not suitable for long-distance and underwater optical communication that requires high-power optical transmitter devices. Therefore, how to improve the communication performance of conventional-size LED is also a key issue at present.

The authors of an article published in Opto-Electronic Science studied a wavelength division multiplexing visible light communication system based on multi-color LED. The system uses a Si substrate GaN-based LED with a 3D structured quantum well. In the active layer of this LED, there is a three-dimensional structure (“V” shaped pit, or V-pit) with a hexagonal profile, opening towards the P-type GaN layer.

With the large-scale commercial use of 5G, global academia and industry have started research on the next-generation mobile communication technology (6G).

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Scientists have been exploring both experimental and theoretical ways to prove quantum supremacy.

Ramis Movassagh, a researcher at Google Quantum AI, recently had a study published in the journal Nature Physics. Here, he has reportedly demonstrated in theory that simulating random quantum circuits and determining their output will be extremely difficult for classical computers. In other words, if a quantum computer solves this problem, it can achieve quantum supremacy.

Continue reading “How can quantum computers be better than classical computers?” »