Universal noise in continuous transport measurements of interacting fermions

Shun Uchino, Masahito Ueda, Jean Philippe Brantut

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


We propose and analyze continuous measurements of atom number and atomic currents using dispersive probing in an optical cavity. For an atom-number measurement in a closed system, we relate both the detection noise and the heating rate due to measurement backaction to Tan's contact and identify an emergent universal quantum nondemolition (QND) regime in the good-cavity limit. We then show that such a continuous QND measurement of atom number serves as a quantum-limited current transducer in a two-terminal setup. We derive a universal bound on the precision of the current measurement, which results from a trade-off between detection noise and backaction of the atomic current measurement. Our results apply regardless of the strength of interaction or the state of matter and set fundamental bounds on future precision measurements of transport properties in cold-atom quantum simulators.

Original languageEnglish
Article number063619
JournalPhysical Review A
Issue number6
Publication statusPublished - 2018 Dec 17

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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