ELFT HÍRADÓ

[Janos Asboth <asboth.janos AT wigner.mta.hu>]

WIGNER SZFI SZEMINÁRIUMANNA SANPERA

(Universitat Autonoma de Barcelona,
vendéglátó: Szirmai Gergely)
"Quantum metrology in thermal states"

Időpont: 2016. április 29. (péntek) 10:00
Hely: MTA Wigner FK SZFI, I. épület 1. emeleti Tanácsterem
Összefoglaló:

The unknown temperature of a sample can be estimated with minimal
disturbance by putting it in thermal contact with an individual quantum
probe. If the interaction time is sufficiently long so that the probe
thermalizes, the temperature can be read-out directly from its steady
state. Here we prove that the optimal quantum probe, acting as a
thermometer with maximal thermal sensitivity, is an effective two-level
atom with a maximally degenerate excited state. When the total interaction
time is insufficient to produce full thermalization, we optimize the
estimation protocol by breaking it down into sequential stages of probe
preparation, thermal contact, and measurement. We observe that frequently
interrogated probes initialized in the ground state achieve the best
performance. For both fully and partly thermalized thermometers, the
sensitivity grows significantly with the number of levels, though
optimization over their energy spectrum remains always crucial.

Phys. Rev. Lett. 114, 220405 (2015)

*Részletes információ:* http://www.szfki.hu/seminar
Minden érdeklődőt szívesen látunk!

Asbóth János
szfi-seminar AT wigner.mta.hu