Lorenza Viola

Size and Memory Both Matter in Quantum Computing

With their promise of unimaginable speed and huge capacity, quantum computers stand to revolutionize the world of information processing. They have the potential to be vastly more powerful than our current digital devices, with the ability to solve important computational problems and simulate complex physical systems with unprecedented efficiency.

Quantum computing operates at the subatomic level, where the familiar laws of classical physics don’t apply. A different set of rules—quantum mechanics—comes into play to explain the behavior of matter and energy on the atomic and subatomic scale—in essence, a different reality from the everyday, observable world.

Unlike today’s silicon-based microprocessors that manipulate ones and zeros as bits and bytes, quantum computing uses quantum physics to represent and process information that is stored in quantum bits or “qubits.” A qubit can be a one, a zero, and everything in between, simultaneously, and can be utilized by physical systems as different as the “spin” of an electron in a trapped atom and a semiconductor quantum device.

Quantum Data Storage Breakthrough (Forbes)

A team of researchers from Dartmouth and the University of Sydney has developed a new method to preserve quantum information, reports Forbes.

The inability to preserve information that is error-free has inhibited the development of practical quantum computing, explains Forbes. The new method being developed by scientists at Dartmouth and Sydney could be a breakthrough, the article explains.

Dartmouth’s Lorenza Viola, a professor of physics and astronomy, and Kaveh Khodjasteh Lakelayeh, a research assistant professor, are co-authors of the study, “Designing a Practical High-Fidelity Long-Time Quantum Memory,” published June 19 in Nature Communications.

Forbes notes that in their paper, the researchers write, “Developing techniques for the preservation of arbitrary quantum states—that is, quantum memory—in realistic, noisy physical systems is vital if we are to bring quantum-enabled applications including secure communications and quantum computation to reality.”

Lorenza Viola, Department of Physics and Astronomy, Dartmouth College

Topic: "Untangling Entanglement: An Observer-Dependent Perspective"  (Video)

ABSTRACT: Entanglement is one of the most fundamental and yet most elusive properties of quantum mechanics. Not only does entanglement play a central role in quantum information science, it also provides an increasingly prominent bridging notion across different subfields of Physics --- including quantum foundations, quantum gravity, quantum statistical mechanics, and beyond. The property of a state being entangled or not is by no means unambiguously defined. Rather, it depends strongly on how we decide to regard the whole as composed of its part or, more generally, on the restricted ways in which we are able to observe and control the system at hand. I will argue how acknowledging the implications of such an operationally constrained point of view leads to a notion of "generalized entanglement," which is directly based on observables and offers added flexibility in a variety of contexts. Time permitting, I will survey some accomplishments of the generalized entanglement program to date, with an eye towards open problems.