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Activity 3

Dynamics of Quantum Systems far from Equilibrium

(MA3) In this Major Activity, we go beyond equilibrium properties of quantum many-body systems and investigate their dynamical evolution. Theoretically, nonequilibrium quantum dynamics is difficult because standard fieldtheoretic many-body techniques apply only to systems in equilibrium, where temperature is a well-defined concept. Quantum dynamics are notoriously difficult to simulate, even for small multiparticle systems. We hope to get a glimpse at the behavior of real material systems, but even an understanding of the dynamics of simple entangled systems would be a landmark accomplishment. This direction is closely related to the development, application, and verification of quantum information hardware because a quantum processor is necessarily operating out-of-equilibrium.

We will study shortterm quench dynamics through the propagation of entanglement, longtime nonequilibrum dynamics as it relates to thermalization, and investigate dynamics in stochastic gauge fields and quantum systems with SU(N) symmetry. The manybody interacting systems we will use in this MA include cold atomic and ionic systems, as well as superconducting qubits with more than 30 elements. The exploration of multiple physical platforms will help to establish whether there is universal dynamical behavior.

Related Articles

  • August 16, 2019

Scientists at the Joint Quantum Institute (JQI) have been steadily improving the performance of ion trap systems, a leading platform for future quantum computers. Now, a team of researchers led by JQI Fellows Norbert Linke and Christopher Monroe has performed a key experiment on five ion-based quantum bits, or qubits. They used laser pulses to simultaneously create quantum connections between...

  • May 17, 2019

From NIST NewsJQI 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...

  • March 6, 2019

Researchers at the Joint Quantum Institute have implemented an experimental test for quantum scrambling, a chaotic shuffling of the information stored among a collection of quantum particles. Their experiments on a group of seven atomic ions, reported in the March 7 issue of Nature, demonstrate a new way to distinguish...

  • November 29, 2017

Two independent teams of scientists, including one from the Joint Quantum Institute, have used more than 50 interacting atomic qubits to mimic magnetic quantum matter, blowing past the complexity of previous demonstrations. The results appear in this week’s issue of Nature.As the basis for its quantum simulation, the JQI team deploys up...

  • November 8, 2017

Computers based on quantum physics promise to solve certain problems much faster than their conventional counterparts. By utilizing qubits—which can have more than just the two values of ordinary bits—quantum computers of the future could perform complex simulations and may solve difficult problems in chemistry, optimization and pattern-recognition.But building a large quantum computer—one...

  • September 27, 2017

In Schrödinger's famous thought experiment, a cat seems to be both dead and alive—an idea that strains credulity. These days, cats still don't act this way, but physicists now regularly create analogues of Schrödinger's cat in the lab by smearing the microscopic quantum world over longer and longer distances.
Such "cat states" have found many homes, promising more sensitive quantum...

  • April 13, 2017

The race to build larger and larger quantum computers is heating up, with several technologies competing for a role in future devices. Each potential platform has strengths and weaknesses, but little has been done to directly compare the performance of early prototypes. Now, researchers at the JQI have performed a first-of-its-kind benchmark test of two small quantum computers built from...

  • March 8, 2017

Consider, for a moment, the humble puddle of water. If you dive down to nearly the scale of molecules, it will be hard to tell one spot in the puddle from any other. You can shift your gaze to the left or right, or tilt your head, and the microscopic bustle will be identical—a situation that physicists call highly symmetric.That all changes abruptly when the puddle freezes. In contrast to...

  • February 24, 2017

When your heart beats, blood courses through your veins in waves of pressure. These pressure waves manifest as your pulse, a regular rhythm unperturbed by the complex internal structure of the body. Scientists call such robust waves solitons, and in many ways they behave more like discrete particles than waves. Soliton theory may aid in the understanding of tsunamis, which—unlike other water...

  • June 24, 2016

Theoretical physicists studying the behavior of ultra-cold atoms have discovered a new source of friction, dispensing with a century-old paradox in the process. Their prediction, which experimenters may soon try to verify, was reported recently in Physical Review Letters.The friction afflicts certain arrangements of atoms in a Bose-Einstein Condensate (BEC), a quantum state of matter in which...

  • June 6, 2016

Nature doesn’t have the best memory. If you fill a box with air and divide it in half with a barrier, it’s easy to tell molecules on the left from molecules on the right. But after removing the barrier and waiting a short while, the molecules get mixed together, and it becomes impossible to tell where a given molecule started. The air-in-a-box system loses any memory of its initial conditions....

Related Publications

Renyi information from entropic effects in one higher dimension, M.F. Maghrebi, JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT, 043102, (2016)