Discrete Time-Crystals in Open Quantum Systems: From Quantum Dots to Molecular Nanomagnets

Seminar

QUEST Center event

Speaker

Yonatan Dubi

Date

21/12/2023 - 13:30 - 12:30Add to Calendar 2023-12-21 12:30:00 2023-12-21 13:30:00 Discrete Time-Crystals in Open Quantum Systems: From Quantum Dots to Molecular Nanomagnets Time crystals are quantum systems characterized by broken discrete time-translational symmetry, manifested by sub-harmonic response to periodic driving (simply put – the frequency of the response of the system is smaller than the frequency of driving). Originally suggested by Wilczek, time-crystals have become a hallmark example of non-trivial self-organization in may-body quantum systems, and has been measured extensively. However, the vast majority (if not all) of the measurements of time crystals are done via optical means, which present various limitations and challenges. It would be highly beneficial to be able to measure time-crystalline behavior in other experimental setups, but this presents a challenge, because many experimental setups are actually open to an environment, and common wisdom is that opening a quantum system to an environment is detrimental to the time-crystalline phase. We thus ask two questions: (1) what are the conditions under which a time-crystal state can survive opening the driven system to an external environment? (2) which new nanoscale systems can exhibit time-crystal order? To answer these questions, we use the theory of open quantum systems (in Lindblad form), and formulate a symmetry condition which we call “weak local dynamical symmetry”, which guarantees the stability of the time-crystal state even if an environment is present. We show that such conditions can be met in transport measurements of driven quantum dot arrays, where the current holds the signature of the time-crystal phase. Finally, we discuss the possibility of measuring time-crystalline behavior in molecular nano-magnet arrays, which display a unique, and to some extent yet unexplained, dynamical features. [1] S. Sarkar and Y. Dubi, Signatures of discrete time-crystallinity in transport through an open Fermionic chain, Nature Communications Physics 5, 155 (2022). [2] S. Sarkar and Y. Dubi, Emergence and Dynamical Stability of a Charge Time-Crystal in a Current-Carrying Quantum Dot Simulator, Nano Letters 22, 11, 4445 (2022) [3] S. Sarkar and Y. Dubi, Time crystals in molecular nanomagnet arrays, Nano Letters (under review) Conference room on the 0th floor of Resnick building Department of Physics physics.dept@mail.biu.ac.il Asia/Jerusalem public

Place

Conference room on the 0th floor of Resnick building

Abstract

Time crystals are quantum systems characterized by broken discrete time-translational symmetry, manifested by sub-harmonic response to periodic driving (simply put – the frequency of the response of the system is smaller than the frequency of driving). Originally suggested by Wilczek, time-crystals have become a hallmark example of non-trivial self-organization in may-body quantum systems, and has been measured extensively. However, the vast majority (if not all) of the measurements of time crystals are done via optical means, which present various limitations and challenges. It would be highly beneficial to be able to measure time-crystalline behavior in other experimental setups, but this presents a challenge, because many experimental setups are actually open to an environment, and common wisdom is that opening a quantum system to an environment is detrimental to the time-crystalline phase.

We thus ask two questions: (1) what are the conditions under which a time-crystal state can survive opening the driven system to an external environment? (2) which new nanoscale systems can exhibit time-crystal order?

To answer these questions, we use the theory of open quantum systems (in Lindblad form), and formulate a symmetry condition which we call “weak local dynamical symmetry”, which guarantees the stability of the time-crystal state even if an environment is present. We show that such conditions can be met in transport measurements of driven quantum dot arrays, where the current holds the signature of the time-crystal phase. Finally, we discuss the possibility of measuring time-crystalline behavior in molecular nano-magnet arrays, which display a unique, and to some extent yet unexplained, dynamical features.

[1] S. Sarkar and Y. Dubi, Signatures of discrete time-crystallinity in transport through an open Fermionic chain, Nature Communications Physics 5, 155 (2022).

[2] S. Sarkar and Y. Dubi, Emergence and Dynamical Stability of a Charge Time-Crystal in a Current-Carrying Quantum Dot Simulator, Nano Letters 22, 11, 4445 (2022)

[3] S. Sarkar and Y. Dubi, Time crystals in molecular nanomagnet arrays, Nano Letters (under review)

Last Updated Date : 18/12/2023