Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: particle 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.

Read more | >

A Washington State University research team has found that nanoscale particles of the most commonly used plastics tend to move through the water supply, especially in fresh water, or settle out in wastewater treatment plants, where they end up as sludge, in landfills, and often as fertilizer.

Neither scenario is good.

“We are drinking lots of plastics,” said Indranil Chowdhury, an assistant professor in WSU’s Department of Civil and Environmental Engineering, who led the research. “We are drinking almost a few grams of plastics every month or so. That is concerning because you don’t know what will happen after 20 years.”

Read more | >

A team of scientists in Australia claim to have stumbled on a breakthrough discovery that will have “major implications” for the future of quantum computing.

Describing the find as a “happy accident,” engineers at the University of New South Wales Sydney found a way to control the nucleus of an atom using electric fields rather than magnetic fields—which they have claimed could now open up a “treasure trove of discoveries and applications.”

Read more | >

Magnetite is the oldest magnetic material known to humans, yet researchers are still mystified by certain aspects of its properties.

For example, when the temperature is lowered below 125 kelvins, changes from a metal to an insulator, its atoms shift to a new lattice structure, and its charges form a complicated ordered pattern. This extraordinarily complex phase transformation, which was discovered in the 1940s and is known as the Verwey transition, was the first metal-insulator transition ever observed. For decades, researchers have not understood exactly how this phase transformation was happening.

According to a paper published March 9 in Nature Physics, an international team of experimental and theoretical researchers discovered fingerprints of the quasiparticles that drive the Verwey transition in magnetite. Using an , the researchers were able to confirm the existence of peculiar electronic waves that are frozen at the and start “dancing together” in a collective oscillating motion as the temperature is lowered.

Read more | >

Scientists in Australia have developed a new approach to reducing the errors that plague experimental quantum computers; a step that could remove a critical roadblock preventing them scaling up to full working machines.

By taking advantage of the infinite geometric space of a particular quantum system made up of bosons, the researchers, led by Dr. Arne Grimsmo from the University of Sydney, have developed quantum correction codes that should reduce the number of physical quantum switches, or qubits, required to scale up these machines to a useful size.

“The beauty of these codes is they are ‘platform agnostic’ and can be developed to work with a wide range of quantum hardware systems,” Dr. Grimsmo said.

Read more | >

A happy accident in the laboratory has led to a breakthrough discovery that not only solved a problem that stood for more than half a century, but has major implications for the development of quantum computers and sensors. In a study published today in Nature, a team of engineers at UNSW Sydney has done what a celebrated scientist first suggested in 1961 was possible, but has eluded everyone since: controlling the nucleus of a single atom using only electric fields.

“This discovery means that we now have a pathway to build quantum computers using single-atom spins without the need for any oscillating magnetic field for their operation,” says UNSW’s Scientia Professor of Quantum Engineering Andrea Morello. “Moreover, we can use these nuclei as exquisitely precise sensors of electric and magnetic fields, or to answer fundamental questions in quantum science.”

That a nuclear spin can be controlled with electric, instead of magnetic fields, has far-reaching consequences. Generating magnetic fields requires large coils and high currents, while the laws of physics dictate that it is difficult to confine magnetic fields to very small spaces—they tend to have a wide area of influence. Electric fields, on the other hand, can be produced at the tip of a tiny electrode, and they fall off very sharply away from the tip. This will make control of individual atoms placed in nanoelectronic devices much easier.

Read more | >

Collisions between beams of gravitons could convert the hypothesized particles into photons, producing a potentially detectable radio signal that would accompany some gravitational waves.

If gravity and quantum mechanics are to be unified, gravitational waves—usually studied as a classical phenomenon using general relativity—must comprise hypothesized particles called gravitons. In theory, gravitons can interact with each other to produce photons, but these interactions were thought to be vanishingly rare and impossible to detect. In new theoretical work, Raymond Sawyer of the University of California, Santa Barbara, finds that in certain cases, colliding gravitational waves could produce enough radio frequency photons to yield a detectable signal.

Read more | >

An international team of researchers, affiliated with UNIST has for the first time succeeded in demonstrating the ionization cooling of muons. Regarded as a major step in being able to create the world’s most powerful particle accelerator, this new muon accelerator is expected to provide a better understanding of the fundamental constituents of matter.

This breakthrough has been carried out by the Muon Ionization Cooling Experiment (MICE) collaboration, which includes many UK scientists, as well as Professor Moses Chung and his research team in the School of Natural Sciences at UNIST. Their findings have been published in the online version of Nature on February 5, 2020.

“We have succeeded in realizing muon ionization cooling, one of our greatest challenges associated with developing muon accelerators,” says Professor Chung. “Achievement of this is considered especially important, as it could change the paradigm of developing the Lepton Collider that could replace the Neutrino Factory or the Large Hadron Collider (LHC).”

Read more | >

Circa 2017 o.o

Lightning is nuts. It’s a supercharged bolt of electricity extending from the sky to the ground that can kill people. But it can also produce nuclear reactions, according to new research.

Scientists have long known that thunderstorms can produce high-energy radiation, like this one from December, 2015 that blasted a Japanese beach town with some gamma radiation. But now, another team of researchers in Japan are reporting conclusive evidence of these gamma rays setting off atom-altering reactions like those in a nuclear reactor.

Read more | >

In the 1970s, physicists uncovered a potential symmetry that united all the kinds of particles in our universe. This connection, known as supersymmetry, relies on the strange quantum property of spin, and could help unlock a new understanding of physics.

Read more | >