Observation of dynamical phase transitions in a topological nanomechanical system

Dynamical phase transitions (DPTs), characterized by nonanalytic behaviors in time domain, extend the equilibrium phase transitions to far-from-equilibrium situations. It has been predicted that DPTs can be precisely identified by the discontinuities of the Pancharatnam geometric phase (PGP) during...

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Bibliographic Details
Published in:Physical review. B 2019-07, Vol.100 (2), p.1, Article 024310
Main Authors: Tian, Tian, Ke, Yongguan, Zhang, Liang, Lin, Shaochun, Shi, Zhifu, Huang, Pu, Lee, Chaohong, Du, Jiangfeng
Format: Article
Language:English
Subjects:
Equilibrium
Oscillators
Phase transitions
Robustness (mathematics)
Time dependence
Topology
Vibration measurement
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Summary:Dynamical phase transitions (DPTs), characterized by nonanalytic behaviors in time domain, extend the equilibrium phase transitions to far-from-equilibrium situations. It has been predicted that DPTs can be precisely identified by the discontinuities of the Pancharatnam geometric phase (PGP) during the time evolution. However, PGP always mixes with dynamical phase and the experimental observation of DPTs by PGP is still absent. Here, we theoretically present a novel scheme for eliminating the dynamical phase by taking advantage of chiral symmetry in the Su-Schrieffer-Heeger (SSH) model and experimentally observe DPTs by directly measuring PGP in a quenched topological nanomechanical lattice. Time-dependent topological structures of the SSH model are configured by eight strong-coupled high-quality-factor nanomechanical oscillators. By measuring the vibration phase and the normalized amplitude of the edge oscillator, we show a direct classical analog of DPTs. Furthermore, we experimentally demonstrate the robustness of DPTs against weak structure disorders, and numerically explore the relation between DPTs and the equilibrium phase boundary. This work not only establishes the quantitative method to identify DPTs, but also opens the door for studying nonequilibrium topological dynamics with a well-controlled nanomechanical system.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.100.024310