del Pino Gutierrez, Javier

Date:   Wednesday, October 21, 2020
Time:   14:00
Place:   scheduled Zoom meeting
Host:    Oded Zilberberg

Synthetic magnetic fields for Hermitian and non-Hermitian topologically-protected states in nano-optomechanical arrays

Javier del Pino Gutierrez
AMOLF, Netherlands

Synthetic magnetic fields can be harnessed to engineer unconventional routing of excitations in bosonic systems and localization phenomena by mimicking the breaking of time-reversal symmetry of electrons in electromagnetic fields. Optomechanical systems offer a route towards Aharonov-Bohm effects for mechanical oscillators - akin to electron paths traversed by magnetic fields - in which artificial gauge fields
for mechanical states are engendered as a result of temporal modulation and retardation of radiation pressure [1]. We study the emergence of nonreciprocal and topologically nontrivial phonon transport in nano-optomechanical networks. We develop on-chip nanophotonic systems in which multiple mechanical modes are coupled through suitable laser control fields that imprint nonreciprocal Peierls phases. This mechanism can break time-reversal symmetry and introduce controlled gain and loss at will on any of the network link and nodes. We reveal the emergence of nanomechanical circulation, helical quantum Hall states, and chiral thermal transport in phononic 'meta-molecules'. Exploiting optomechanical gain, we study the combination of broken time-reversal symmetry and non-Hermiticity, in networks of increasing size controlled through synthetic electric and magnetic fields.

[1] Mathew, J.P., Pino, J.d. & Verhagen, E. Synthetic gauge fields for phonon transport in a nano-optomechanical system. Nat. Nanotechnol. 15, 198-202 (2020).