Continuous Real-Time Tracking of a Quantum Phase Below the Standard Quantum Limit
| Autor: | Graham P. Greve, Baochen Wu, Athreya Shankar, James K. Thompson, Murray Holland |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Physics
Quantum Physics education.field_of_study Atomic Physics (physics.atom-ph) Quantum limit Population Phase (waves) FOS: Physical sciences General Physics and Astronomy Tracking (particle physics) 01 natural sciences Physics - Atomic Physics 3. Good health Quantum mechanics 0103 physical sciences Quantum Physics (quant-ph) 010306 general physics education Spin (physics) Real time tracking Quantum |
| Zdroj: | Physical Review Letters. 122 |
| ISSN: | 1079-7114 0031-9007 |
| DOI: | 10.1103/physrevlett.122.233602 |
| Popis: | We propose a scheme for continuously measuring the evolving quantum phase of a collective spin composed of $N$ pseudospins. Quantum non-demolition measurements of a lossy cavity mode interacting with an atomic ensemble are used to directly probe the phase of the collective atomic spin without converting it into a population difference. Unlike traditional Ramsey measurement sequences, our scheme allows for real-time tracking of time-varying signals. As a bonus, spin-squeezed states develop naturally, providing real-time phase estimation significantly more precise than the standard quantum limit of $\Delta \phi_\text{SQL} = 1/\sqrt{N}$ radians. Comment: 6 + 6 pages, 3 + 2 figures, includes Supplemental Material; close to journal version |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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