Freezing a quantum magnet by repeated quantum interference: An experimental realization

Abstract

We experimentally demonstrate the phenomenon of dynamical many-body freezing in a periodically driven Ising chain. Theoretically [A. Das, Phys. Rev. B 82, 172402 (2010)], for certain values of the drive parameters all fundamental degrees of freedom contributing to the response dynamics freeze for all time and for arbitrary initial state. Also, since the condition of freezing involves only the drive parameters and not the quantization of the momentum (i.e., the system size), our simulation with a small (3-spin) chain captures all salient features of the freezing phenomenon predicted for the infinite chain. Using optimal control techniques, we realize high-fidelity cosinemodulated drive, and observe nonmonotonic freezing of magnetization at specific frequencies of modulation. Time evolution of the excitations in momentum space has been tracked directly through magnetization measurements.

Universal high-frequency behavior of periodically driven systems: from dynamical stabilization to Floquet engineering

“…By choosing α to coincide with the zero of the Bessel function, periodically driven spin systems can exhibit dynamical freezing [190,191]. We derive the leading Ω −1 -corrections by computing the next term in the Magnus August 20, 2015 Advances in Physics Floquet˙review˙v5.0 (High-Frequency) expansion.…”

Speeding up maximum population transfer in periodically driven multi-level quantum systems

“…The approach could also be used to speed up other quantum transitions process, like molecular isomerization, etc. Along the same lines, it would be of interest to study the implementation of our protocol in many-body systems, especially how it relates with interesting many-body phenomena such as dynamical many-body freezing 18,19 , that has been observed recently in Ising chains at certain driving frequencies 20 . This is particularly interesting, as such phenomena could limit the frequencies that can be used to control the state of the system, and will be analyzed in a future manuscript.…”

Quantum systems under frequency modulation

“…The vanishing of tunneling by modulation in a lattice has been termed "dynamic localization" [77]. It has long been studied theoretically and experimentally in different systems [13], for example, in onedimensional transverse Ising chains [285,286] and semiconductor superlattices [287]. A phenomenon more or less similar to dynamical localization occurs in a double-well potential [13] and is discussed in section 3.2.…”