Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userNonclassical character of statistical mixtures of the single-photon and vacuum optical states
102
0
0.0
(
0
)
Added by
Alexander I. Lvovsky
Publication date
2001
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
We demonstrate, theoretically and experimentally, that statistical mixtures of the vacuum state |0> and the single-photon Fock state |1> are nonclassical according to the Vogel criterion (W. Vogel, Phys. Rev. Lett. 84, 1849 (2000)), regardless of the vacuum fraction. The ensembles are synthesized via conditional measurements on biphotons generated by means of parametric downconversion, and their quadrature statistics are measured using balanced homodyne detection. A comparative review of various quantum state nonclassicality criteria is presented.
rate research
Read More
Photon-number correlation measurements are performed on bright squeezed vacuum states using a standard Bell-test setup, and quantum correlations are observed for conjugate polarization-frequency modes. We further test the entanglement witnesses for these states and demonstrate the violation of the separability criteria, which infers that all the macroscopic Bell states, containing typically $10^6$ photons per pulse, are polarization entangled. The study also reveals the symmetry of macroscopic Bell states with respect to local polarization transformations.
We report demonstrations of both quadrature squeezed vacuum and photon number difference squeezing generated in an integrated nanophotonic device. Squeezed light is generated via strongly driven spontaneous four-wave mixing below threshold in silicon nitride microring resonators. The generated light is characterized with both homodyne detection and direct measurements of photon statistics using photon number-resolving transition edge sensors. We measure $1.0(1)$~dB of broadband quadrature squeezing (${sim}4$~dB inferred on-chip) and $1.5(3)$~dB of photon number difference squeezing (${sim}7$~dB inferred on-chip). Nearly-single temporal mode operation is achieved, with measured raw unheralded second-order correlations $g^{(2)}$ as high as $1.95(1)$. Multi-photon events of over 10 photons are directly detected with rates exceeding any previous quantum optical demonstration using integrated nanophotonics. These results will have an enabling impact on scaling continuous variable quantum technology.
Travelling modes of single-photon-added coherent states (SPACS) are characterized via optical homodyne tomography. Given a set of experimentally measured quadrature distributions, we estimate parameters of the state and also extract information about the detector efficiency. The method used is a minimal distance estimation between theoretical and experimental quantities, which additionally allows to evaluate the precision of estimated parameters. Given experimental data, we also estimate the lower and upper bounds on fidelity. The results are believed to encourage preciser engineering and detection of SPACS.
We employ the quantum state of a single photon entangled with the vacuum (|1,0>-|0,1>), generated by a photon incident upon a symmetric beam splitter, to teleport single-mode quantum states of light by means of the Bennett protocol. Teleportation of coherent states results in truncation of their Fock expansion to the first two terms. We analyze the teleported ensembles by means of homodyne tomography and obtain fidelities of up to 99 per cent for low source state amplitudes. This work is an experimental realization of the quantum scissors device proposed by Pegg, Phillips and Barnett (Phys. Rev. Lett. 81, 1604 (1998))
It is demonstrated that a weak measurement of the squared quadrature observable may yield negative values for coherent states. This result cannot be reproduced by a classical theory where quadratures are stochastic $c$-numbers. The real part of the weak value is a conditional moment of the Margenau-Hill distribution. The nonclassicality of coherent states can be associated with negative values of the Margenau-Hill distribution. A more general type of weak measurement is considered, where the pointer can be in an arbitrary state, pure or mixed.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
