In a Smooth Move, Ions Ditch Disorder and Keep Their Memories
Scientists have found a new way to create disturbances that do not fade away. Instead of relying on disorder to freeze things in place, they tipped a quantum container to one side—a trick that is easier to conjure in the lab. A collaboration between the experimental group of College Park Professor Christopher Monroe and the theoretical group of JQI Fellow Alexey Gorshkov, who is also a Fellow of the Joint Center for Quantum Information and Computer Science, has used trapped ions to implement this new technique, confirming that it prevents their quantum particles from reaching equilibrium. The team also measured the slowed spread of information with the new tipping technique for the first time. They published their results recently in the journal Nature.
Graphene’s Magic Act Relies on a Small Twist
Atomically thin sheets of carbon, called graphene, have caught many scientists' attention in recent years. Researchers have discovered that stacking layers of graphene two or three at a time and twisting the layers opens fertile new territory for them to explore. Research into these stacked sheets of graphene is like the Wild West, complete with the lure of striking gold and the uncertainty of uncharted territory. Researchers at JQI and the Condensed Matter Theory Center (CMTC) at the University of Maryland are busy creating the theoretical physics foundation that will be a map of this new landscape. And there is a lot to map; the phenomena in graphene range from the familiar like magnetism to more exotic things like strange metallicity, different versions of the quantum Hall effect, and the Pomeranchuk effect—each of which involve electrons coordinating to produce unique behaviors. One of the most promising veins for scientific treasure is the appearance of superconductivity (lossless electrical flow) in stacked graphene.
Foundational Step Shows Quantum Computers Can Be Better Than the Sum of Their Parts
Pobody’s nerfect—not even the indifferent, calculating bits that are the foundation of computers. But JQI Fellow Christopher Monroe’s group, together with colleagues from Duke University, have made progress toward ensuring we can trust the results of quantum computers even when they are built from pieces that sometimes fail. They have shown in an experiment, for the first time, that an assembly of quantum computing pieces can be better than the worst parts used to make it. In a paper published in the journal Nature on Oct. 4, 2021, the team shared how they took this landmark step toward reliable, practical quantum computers. In their experiment, the researchers combined several qubits—the quantum version of bits—so that they functioned together as a single unit called a logical qubit. They created the logical qubit based on a quantum error correction code so that, unlike for the individual physical qubits, errors can be easily detected and corrected, and they made it to be fault-tolerant—capable of containing errors to minimize their negative effects. This is the first time that a logical qubit has been shown to be more reliable than the most error-prone step required to make it.
Novel Design May Boost Efficiency of On-Chip Frequency Combs
On the cover of the Pink Floyd album Dark Side of the Moon, a prism splits a ray of light into all the colors of the rainbow. This multicolored medley, which owes its emergence to the fact that light travels as a wave, is almost always hiding in plain sight; a prism simply reveals that it was there.
Researchers Uncover a ‘Shortcut’ to Thermodynamic Calculations Using Quantum Computers
A collaboration between researchers at JQI and North Carolina State University has developed a new method that uses a quantum computer to measure the thermodynamic properties of a system. The team shared the new approach in a paper published August 18, 2021, in the journal Science Advances.