Entangled qubits in a non-Gaussian quantum state

Kiesel, T.; Vogel, W.; Hage, B.; Schnabel, R.

doi:10.1103/physreva.83.062319

Cited by 23 publications

(26 citation statements)

References 29 publications

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“…We have shown how WFH can be used to deconstruct phase-dependent measurements on two-mode entangled states into their constituent Fock layers. The ability to operate devices at the interface of wave and particle regimes opens up new possibilities for quantum information processing [35]. Thus, our work provides a new insight on such resources within the broader investigations on hybrid continuous/discrete-variable coding [36][37][38][39][40].…”

Section: Discussionmentioning

confidence: 84%

Observing optical coherence across Fock layers with weak-field homodyne detectors

et al. 2014

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Quantum properties of optical modes are typically assessed by observing their photon statistics or the distribution of their quadratures. Both particle-and wave-like behaviours deliver important information and each may be used as a resource in quantum-enhanced technologies. Weak-field homodyne (WFH) detection provides a scheme that combines the wave-and particle-like descriptions. Here we show that it is possible to observe a wave-like property such as the optical coherence across Fock basis states in the detection statistics derived from discrete photon counting. We experimentally demonstrate these correlations using two WHF detectors on each mode of two classes of two-mode entangled states. Furthermore, we theoretically describe the response of WHF detection on a two-mode squeezed state in the context of generalized Bell inequalities. Our work demonstrates the potential of this technique as a tool for hybrid continuous/discrete-variable protocols on a phenomenon that explicitly combines both approaches.

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Section: Discussionmentioning

confidence: 84%

Observing optical coherence across Fock layers with weak-field homodyne detectors

et al. 2014

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“…Experimental reconstructions of nonclassicality quasiprobabilities have been performed for a squeezed state measured for a discrete set of phases [25], requiring additional interpolations (for details see the supplement to [25]). For the single-photon-added thermal state [26] on the other hand, phase properties need not be considered in view of the radial symmetry of this state. The regularization method was generalized for multi-mode radiation fields [27] to uncover any simultaneous quantum correlation among the modes in the sense of the Glauber-Sudarshan notion.…”

Section: Introductionmentioning

confidence: 99%

Continuous sampling of the squeezed-state nonclassicality

et al. 2015

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We report the direct -continuous in phase -sampling of a regularized P function, the so-called nonclassicality quasiprobability, for squeezed light. Through their negativities, the resulting phasespace representation uncovers the quantum character of the state. In contrast to discrete phaselocked measurements, our approach allows an unconditional verification of nonclassicality by getting rid of interpolation errors due to fixed phases. To realize the equal phase distribution of measured quadratures, a data selection is implemented with quantum random numbers created by measuring the vacuum noise. The continuously measured squeezed field was generated in an optical parametric amplifier. Suitable pattern functions for obtaining the regularized P function are investigated. The significance of detecting negativities in our application is determined. The sampling of nonclassicality quasiprobabilities is shown to be a powerful and universal method to visualize quantum effects within arbitrary quantum states.

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“…Spectroscopy with quantum light, known as quantum spectroscopy [9][10][11][12][13], is made possible by recent progress in photon quantum state engineering [14][15][16][17][18][19][20][21]. Quantum spectroscopy had been applied to overcome the time/frequency Fourier uncertainty in Raman signals [22] to control two-exciton states in photosynthetic complexes [11] and to obtain nonlinear signals with weak fields, thanks to the improved scaling of signals with light intensity: e.g.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear fluctuations and dissipation in matter revealed by quantum light

Mukamel¹,

Dorfman²

2015

Phys. Rev. A

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Quantum optical fields offer numerous control knobs which are not available with classical light and may be used for monitoring the properties of matter by novel types of spectroscopy. It has been recently argued that such quantum spectroscopy signals can be obtained by a simple averaging of their classical spectroscopy counterparts over the Glauber-Sudarshan quasiprobability distribution of the quantum field; the quantum light thus merely provides a novel gating window for the classical response functions. We show that this argument only applies to the linear response and breaks down in the nonlinear regime. The quantum response carries additional valuable information about response and spontaneous fluctuations of matter that may not be retrieved from the classical response by simple data processing. This is connected to the lack of a nonlinear fluctuation-dissipation relation. *

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Entangled qubits in a non-Gaussian quantum state

Cited by 23 publications

References 29 publications

Observing optical coherence across Fock layers with weak-field homodyne detectors

Observing optical coherence across Fock layers with weak-field homodyne detectors

Continuous sampling of the squeezed-state nonclassicality

Nonlinear fluctuations and dissipation in matter revealed by quantum light

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