We are happy to announce our next seminar.
Speaker: Abolfazl Bayat (University of Electronic Science and Technology of China, CHN)
When: Thursday, 14th January 2020, 3PM (CET time)
Where: online (Zoom) zoom.us/my/aula.x
Title: Driving enhanced quantum sensing in partially accessible many-body systems
Ground state criticality of many-body systems is a resource for quantum enhanced sensing, namely Heisenberg precision limit, provided that one has access to the whole system. We show that for partial accessibility the sensing capacity of a block in the ground state reduces to sub-Heisenberg limit. To compensate for this, we drive the system periodically and use the local steady state for quantum sensing. Remarkably, the steady state sensing shows a significant enhancement in its precision in comparison with the ground state and even shows super-Heisenberg scaling for a certain range of frequencies. The origin of this precision enhancement is found to be the closing of the Floquet gap. This is in close correspondence with the role of the vanishing energy gap
at criticality for quantum enhanced ground state sensing with global accessibility.