Fundamental quantum limits in ellipsometry

The Les Houches Summer School 2015 covered the emerging fields of cavity optomechanics and quantum nanomechanics. Optomechanics is flourishing and its concepts and techniques are now applied to a wide range of topics. Modern quantum optomechanics was born in the late 70s in the framework of gravitational wave interferometry, initially focusing on the quantum limits of displacement measurements. Carlton Caves, Vladimir Braginsky, and others realized that the sensitivity of the anticipated large-scale gravitational-wave interferometers (GWI) was fundamentally limited by the quantum fluctuations of the measurement laser beam. After tremendous experimental progress, the sensitivity of the upcoming next generation of GWI will effectively be limited by quantum noise. In this way, quantum-optomechanical effects will directly affect the operation of what is arguably the world’s most impressive precision experiment. However, optomechanics has also gained a life of its own with a focus on the quantum aspects of moving mirrors. Laser light can be used to cool mechanical resonators well below the temperature of their environment. After proof-of-principle demonstrations of this cooling in 2006, a number of systems were used as the field gradually merged with its condensed matter cousin (nanomechanical systems) to try to reach the mechanical quantum ground state, eventually demonstrated in 2010 by pure cryogenic techniques and a year later by a combination of cryogenic and radiation-pressure cooling. The book covers all aspects—historical, theoretical, experimental—of the field, with its applications to quantum measurement, foundations of quantum mechanics and quantum information. Essential reading for any researcher in the field.

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Quantum limits to all-optical phase shifts in a Kerr nonlinear medium

Physical Review A ◽

10.1103/physreva.45.1919 ◽

1992 ◽

Vol 45 (3) ◽

pp. 1919-1923 ◽

Cited By ~ 53

Author(s):

Barry C. Sanders ◽

Gerard J. Milburn

Keyword(s):

Nonlinear Medium ◽

Phase Shifts ◽

Optical Phase ◽

All Optical ◽

Quantum Limits

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Quantum limits to mass sensing in a gravitational field

Journal of Physics A Mathematical and Theoretical ◽

10.1088/1751-8121/aa6cc5 ◽

2017 ◽

Vol 50 (23) ◽

pp. 235301 ◽

Cited By ~ 8

Author(s):

Luigi Seveso ◽

Valerio Peri ◽

Matteo G A Paris

Keyword(s):

Gravitational Field ◽

Mass Sensing ◽

Quantum Limits

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Monitoring dispersive samples with single photons: the role of frequency correlations

Quantum Measurements and Quantum Metrology ◽

10.1515/qmetro-2017-0008 ◽

2017 ◽

Vol 4 (1) ◽

Cited By ~ 1

Author(s):

Emanuele Roccia ◽

Marco G. Genoni ◽

Luca Mancino ◽

Ilaria Gianani ◽

Marco Barbieri ◽

...

Keyword(s):

Degrees Of Freedom ◽

Simultaneous Estimation ◽

Single Photons ◽

Estimation Scheme ◽

Correlation Parameters ◽

Two Parameters ◽

Quantum Limits ◽

Cramer Rao Bound ◽

Down Conversion

AbstractThe physics that governs quantum monitoring may involve other degrees of freedom than the ones initialised and controlled for probing. In this context we address the simultaneous estimation of phase and dephasing characterizing a dispersive medium, and we explore the role of frequency correlations within a photon pair generated via parametric down-conversion, when used as a probe for the medium. We derive the ultimate quantum limits on the estimation of the two parameters, by calculating the corresponding quantum Cramér-Rao bound; we then consider a feasible estimation scheme, based on the measurement of Stokes operators, and address its absolute performances in terms of the correlation parameters, and, more fundamentally, of the role played by correlations in the simultaneous achievability of the quantum Cramér- Rao bounds for each of the two parameters.

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