In The News

To mark the 50th anniversary of Physical Review B, editors selected “milestone” papers that have made lasting contributions to condensed matter physics, including one co-written by JQI Fellow Sankar Das Sarma. Das Sarma wrote the selected paper, Dielectric function, screening, and plasmons in two-dimensional graphene, with Euyheon Hwang.

Researchers at JQI and their colleagues have proposed a novel method for finding dark matter, the cosmos’s mystery material that has eluded detection for decades. Dark matter makes up about 27% of the universe; ordinary matter, such as the stuff that builds stars and planets, accounts for just 5% of the cosmos. (A mysterious entity called dark energy, accounts for the other 68%.)

Researchers at the National Institute of Standards and Technology (NIST), JQI and the Department of Physics at the University of Maryland have devised and demonstrated a system that could dramatically increase the performance of communications networks while enabling record-low error rates in detecting even the faintest of signals. The work could potentially decrease the total amount of energy required for state-of-the-art networks by a factor of 10 to 100.

The Department of Energy (DOE) has awarded $115 million over five years to the Quantum Systems Accelerator (QSA), a new research center led by Lawrence Berkeley National Laboratory (Berkeley Lab) that will forge the technological solutions needed to harness quantum information science for discoveries that benefit the world. It will also energize the nation’s research community to ensure U.S. leadership in quantum R&D and accelerate the transfer of quantum technologies from the lab to the marketplace. Sandia National Laboratories is the lead partner of the center.

Researchers have been pushing the frontiers of the quantum world for over a century. And time after time, spin has been a rich source of new physics. Spin is essential when delving into virtually any topic governed by quantum mechanics, from superconductors to the Higgs Boson. In the past couple years, researchers have discovered materials in which electrons behave like their spin has been bumped up, from 1/2 to 3/2. JQI postdoctoral researcher Igor Boettcher explored the new behaviors these spins might produce in a recent paper featured on the cover of Physical Review Letters.

Topological materials have captured the interest of many scientists and may provide the basis for a new era in materials development. On April 10, 2020 in the journal Science Advances, physicists working with Andreas Elben, Jinlong Yu, Peter Zoller and Benoit Vermersch, including JQI Fellow Mohammad Hafezi and former JQI postdoctoral researcher Guanyu Zhu (currently a research staff member at IBM T. J. Watson Research Center), presented a new method for identifying and characterizing topological invariants on various experimental platforms, testing their protocol in a quantum simulator made of neutral atoms.

A high-end race car engine needs all its components tuned and working together precisely to deliver top-quality performance. The same can be said about the processor inside a quantum computer, whose delicate bits must be adjusted in just the right way before it can perform a calculation. Who’s the right mechanic for this quantum tuneup job? According to a team that includes scientists at the National Institute of Standards and Technology (NIST), it’s an artificial intelligence, that’s who.The team’s paper in the journal Physical Review Applied outlines a way to teach an AI to make an interconnected set of adjustments to tiny quantum dots, which are among the many promising devices for creating the quantum bits, or “qubits,” that would form the switches in a quantum computer’s processor.

By cleverly manipulating two properties of a neutron beam, scientists at the National Institute of Standards and Technology (NIST) and their collaborators have created a powerful probe of materials that have complex and twisted magnetic structures.Penetrating deep inside heavyweight materials, yet still able to interact strongly with light elements, neutron beams image hydrogen-bearing liquids in engine parts, storage tanks and fuel cells. The beams can also map the shapes of polymers on the molecular scale, reveal the precise arrangement of atoms in a crystal and chart the distribution of water within growing plants. Neutron beams became even stronger probes when scientists learned how to harness two quantum properties of the beams. One of these properties, formally known as orbital angular momentum, or OAM, refers to the twisting, or rotational motion of a neutron as it travels forward, similar to the whirlpool formed by water as it travels down a drain. The other quantum property, spin, is related to the neutron’s magnetic field, and can be likened to the spinning motion of a top.

JQI researchers have demonstrated a new way to obtain the essential details that describe an isolated quantum system, such as a gas of atoms, through direct observation. The new method gives information about the likelihood of finding atoms at specific locations in the system with unprecedented spatial resolution. With this technique, scientists can obtain details on a scale of tens of nanometers—smaller than the width of a virus. The new experiments use an optical lattice—a web of laser light that suspends thousands of individual atoms—to determine the probability that an atom might be at any given location. Because each individual atom in the lattice behaves like all the others, a measurement on the entire group of atoms reveals the likelihood of an individual atom to be in a particular point in space. Published in the journal Physical Review X, the technique (similar work was published simultaneously by a group at the University of Chicago) can yield the likelihood of the atoms’ locations at well below the wavelength of the light used to illuminate the atoms—50 times better than the limit of what optical microscopy can normally resolve. 

News from NIST Researchers at JILA have, for the first time, isolated groups of a few atoms and precisely measured their multi-particle interactions within an atomic clock. They compared the results with theoretical predictions by NIST colleagues Ana Maria Rey and Paul Julienne and concluded that multi-particle interactions occurred. "This experiment demonstrates a remarkable ability to both measure and calculate the quantum properties of just a handful of atoms held in single optical lattice cells,” says Julienne, who is also a JQI Fellow. "This type of setup is a superb platform for precision measurement and for controlling many-particle quantum dynamics and entanglement, with applications to few-body physics, many-body physics, and quantum information.” The advance will help scientists control interacting quantum matter, which is expected to boost the performance of atomic clocks, many other types of sensors, and quantum information systems. The research is published online in Nature.