scholarly journals Mesoscopic atomic entanglement for precision measurements beyond the standard quantum limit

2009 ◽  
Vol 106 (27) ◽  
pp. 10960-10965 ◽  
Author(s):  
J. Appel ◽  
P. J. Windpassinger ◽  
D. Oblak ◽  
U. B. Hoff ◽  
N. Kjaergaard ◽  
...  
Keyword(s):  
Precision Measurements ◽  
Quantum Limit ◽  
Standard Quantum ◽  
Standard Quantum Limit ◽  
Atomic Entanglement

scholarly journals Beating the classical precision limit with spin-1 Dicke states of more than 10,000 atoms

2018 ◽  
Vol 115 (25) ◽  
pp. 6381-6385 ◽  
Author(s):  
Yi-Quan Zou ◽  
Ling-Na Wu ◽  
Qi Liu ◽  
Xin-Yu Luo ◽  
Shuai-Feng Guo ◽  
...  
Keyword(s):  
Laser Interferometer ◽  
Precision Measurements ◽  
Quantum Limit ◽  
Quantum Metrology ◽  
Standard Quantum ◽  
Standard Quantum Limit ◽  
Precision Limit ◽  
Individual Particles ◽  
Entangled Atoms ◽  
Dicke States

Interferometry is a paradigm for most precision measurements. Using N uncorrelated particles, the achievable precision for a two-mode (two-path) interferometer is bounded by the standard quantum limit (SQL), 1/N, due to the discrete (quanta) nature of individual measurements. Despite being a challenging benchmark, the two-mode SQL has been approached in a number of systems, including the Laser Interferometer Gravitational-Wave Observatory and today’s best atomic clocks. For multimode interferometry, the SQL becomes 1/[(M−1)N] using M modes. Higher precision can also be achieved using entangled particles such that quantum noises from individual particles cancel out. In this work, we demonstrate an interferometric precision of 2.42−1.29+1.76 dB beyond the three-mode SQL, using balanced spin-1 (three-mode) Dicke states containing thousands of entangled atoms. The input quantum states are deterministically generated by controlled quantum phase transition and exhibit close to ideal quality. Our work shines light on the pursuit of quantum metrology beyond SQL.

scholarly journals Entanglement-enhanced matter-wave interferometry in a high-finesse cavity

2021 ◽  
Author(s):  
James Thompson ◽  
Graham Greve ◽  
Chengyi Luo ◽  
Baochen Wu
Keyword(s):  
Cavity Qed ◽  
Degrees Of Freedom ◽  
Inertial Sensors ◽  
Mean Field ◽  
New Physics ◽  
Matter Wave ◽  
Quantum Limit ◽  
Entangled State ◽  
Standard Quantum ◽  
Standard Quantum Limit

Abstract Entanglement is a fundamental resource that allows quantum sensors to surpass the standard quantum limit set by the quantum collapse of independent atoms. Collective cavity-QED systems have succeeded in generating large amounts of directly observed entanglement involving the internal degrees of freedom of laser-cooled atomic ensembles. Here we demonstrate cavity-QED entanglement of external degrees of freedom to realize a matter-wave interferometer of 700 atoms in which each individual atom falls freely under gravity and simultaneously traverses two paths through space while also entangled with the other atoms. We demonstrate both quantum non-demolition measurements and cavity-mediated spin interactions for generating squeezed momentum states with directly observed metrological gain 3.4^{+1.1}_{-0.9} dB and 2.5^{+0.6}_{-0.6} dB below the standard quantum limit respectively. An entangled state is for the first time successfully injected into a Mach-Zehnder light-pulse interferometer with 1.7^{+0.5}_{-0.5} dB of directly observed metrological enhancement. These results open a new path for combining particle delocalization and entanglement for inertial sensors, searches for new physics, particles, and fields, future advanced gravitational wave detectors, and accessing beyond mean-field quantum many-body physics.

scholarly journals The standard quantum limit of coherent beam combining

2019 ◽  
Vol 21 (9) ◽  
pp. 093047 ◽  
Author(s):  
C R Müller ◽  
F Sedlmeir ◽  
V O Martynov ◽  
Ch Marquardt ◽  
A V Andrianov ◽  
...  
Keyword(s):  
Coherent Beam ◽  
Quantum Limit ◽  
Standard Quantum ◽  
Standard Quantum Limit ◽  
Coherent Beam Combining ◽  
Beam Combining

scholarly journals Squeezed-light-driven force detection with an optomechanical cavity in a Mach–Zehnder interferometer

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chang-Woo Lee ◽  
Jae Hoon Lee ◽  
Hyojun Seok
Keyword(s):  
Zehnder Interferometer ◽  
Vacuum Field ◽  
Quantum Limit ◽  
Measurement Sensitivity ◽  
Force Detection ◽  
Detection Scheme ◽  
Standard Quantum ◽  
Standard Quantum Limit ◽  
Optomechanical Cavity ◽  
Mach Zehnder Interferometer

Abstract We analyze the performance of a force detector based on balanced measurements with a Mach–Zehnder interferometer incorporating a standard optomechanical cavity. The system is driven by a coherent superposition of coherent light and squeezed vacuum field, providing quantum correlation along with optical coherence in order to enhance the measurement sensitivity beyond the standard quantum limit. We analytically find the optimal measurement strength, squeezing direction, and squeezing strength at which the symmetrized power spectral density for the measurement noise is minimized below the standard quantum limit. This force detection scheme based on a balanced Mach–Zehnder interferometer provides better sensitivity compared to that based on balanced homodyne detection with a local oscillator in the low frequency regime.

Sign in / Sign up

Export Citation Format

Share Document