HOME | WHAT WE DO | WHO WE ARE | WHAT'S GOING ON | HOW TO JOIN
In most solids, especially near room temperature, quantum mechanics is not as necessary to understand dynamical properties as one might have thought. While understanding the different kinds of order and their excitations frequently requires a quantum description, the various sources of dephasing in solids mean that dynamics is often well described by classical pictures such as diffusion. However, the past decade has seen an explosion in the range of systems that show strongly quantum dynamics, including bulk solids at short time scales, engineered devices such as qubits, and ultracold atomic gases.
Figure 1: Entanglement growth with time is bounded without interactions but increases without limit in the MBL phase.
Sometimes quantum effects act to inhibit thermalization, as in many-body localization, which can be differentiated from Anderson localization (a property of non-interacting classical or quantum waves) by the growth of entanglement entropy (Figure 1, from Bardarson, Pollmann, and Moore, PRL 2012). In systems with a form of equilibration, quantum mechanics can both modify the ultimate equilibrium state and also the hydrodynamical approach to that equilibrium, as in spin chains (Figure 2, from Bulchandani, Vasseur, Karrasch, and Moore, PRL 2018).
Figure 2: Comparison of hydrodynamical predictions with microscopic DMRG numerics for a centrally heated XXZ spin chain.
We are always trying to find and understand new varieties of quantum dynamics, particularly those relevant to experiment. Many aspects of quantum information theory, such as entanglement and the role of measurement, are primarily probed using dynamical experiments, and the advent of quantum computers and emulators is a major driver of research in this area.