scholarly journals Dual form of the phase-space classical simulation problem in quantum optics

Author(s):  
Andrii A. Semenov ◽  
Andrei B Klimov

Abstract In quantum optics, nonclassicality of quantum states is commonly associated with negativities of phase-space quasiprobability distributions.We argue that the impossibility of any classical simulations with phase-space functions is a necessary and sufficient condition of nonclassicality. The problem of such phase-space classical simulations for particular measurement schemes is analysed in the framework of Einstein-Podolsky-Rosen-Bell's principles of physical reality. The dual form of this problem results in an analogue of Bell inequalities. Their violations imply the impossibility of phase-space classical simulations and, as a consequence, nonclassicality of quantum states. We apply this technique to emblematic optical measurements such as photocounting, including the cases of realistic photon-number resolution and homodyne detection in unbalanced, balanced, and eight-port configurations.

Proceedings ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Giovanni Chesi ◽  
Luca Malinverno ◽  
Alessia Allevi ◽  
Romualdo Santoro ◽  
Massimo Caccia ◽  
...  

The study of nonclassical properties of quantum states is a relevant topic for fundamental Quantum Optics and Quantum Information applications. In the mesoscopic domain, promising results have been obtained using photon-number-resolving detectors. Here we show recent results achieved with the class of Silicon Photomultipliers: by a proper analysis of the output signal, the nonclassicality of twin-beam states can be detected and exploited.


Author(s):  
Yiwen Chu ◽  
Mikhail D. Lukin

A common theme in the implementation of quantum technologies involves addressing the seemingly contradictory needs for controllability and isolation from external effects. Undesirable effects of the environment must be minimized, while at the same time techniques and tools must be developed that enable interaction with the system in a controllable and well-defined manner. This chapter addresses several aspects of this theme with regard to a particularly promising candidate for developing applications in both metrology and quantum information, namely the nitrogen-vacancy (NV) centre in diamond. The chapter describes how the quantum states of NV centres can be manipulated, probed, and efficiently coupled with optical photons. It also discusses ways of tackling the challenges of controlling the optical properties of these emitters inside a complex solid state environment.


2017 ◽  
Vol 15 (08) ◽  
pp. 1740016 ◽  
Author(s):  
Alessia Allevi ◽  
Matteo Bina ◽  
Stefano Olivares ◽  
Maria Bondani

Homodyne detection is the most effective detection scheme employed in quantum optics to characterize quantum states. It is based on mixing at a beam splitter the signal to be measured with a coherent state, called the “local oscillator,” and on evaluating the difference of the photocurrents of two photodiodes measuring the outputs of the beam splitter. If the local oscillator is much more intense than the field to be measured, the homodyne signal is proportional to the signal-field quadratures. If the local oscillator is less intense, the photodiodes can be replaced with photon-number-resolving detectors, which have a smaller dynamics but can measure the light statistics. The resulting new homodyne-like detector acquires a hybrid nature, being it capable of yielding information on both the particle-like (statistics) and wave-like (phase) properties of light signals. The scheme has been tested in the measurement of the quadratures of coherent states, bracket states and phase-averaged coherent states at different intensities of the local oscillator.


Author(s):  
Antoine Heidmann ◽  
Pierre-Francois Cohadon

In its simplest form, optomechanics amounts to two complementary coupling effects: mechanical motion changes the path followed by light, but light (through radiation pressure) can drive the mechanical resonator into motion as well. Optomechanics allows one to control resonator motion by laser cooling down to the quantum ground state, or to control light by using back-action in optical measurements and in quantum optics. Its main applications are optomechanical sensors to detect tiny mechanical motions and weak forces, cold damping and laser cooling, and quantum optics. The objectives of this chapter are to provide a brief account of the history of the field, together with its fundamentals. We will in particular review both classical and quantum aspects of optomechanics, together with its applications to high-sensitivity measurements and to control or cool mechanical resonators down to their ground state, with possible applications for tests of quantum theory or for quantum information.


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