Person:
Luis Aina, Alfredo

First Name

Alfredo

Last Name

Luis Aina

URI

https://hdl.handle.net/20.500.14352/75157

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Físicas

Department

Óptica

Area

Optica

Identifiers

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Now showing 1 - 10 of 61

Equivalence between macroscopic quantum superpositions and maximally entangled states: application to phase-shift detection
(Physical review A, 2001) Luis Aina, Alfredo
We demonstrate that the superpositions of macroscopically distinct coherent states are maximally entangled states. Among other possible applications of this result, in this paper we show that the experimental arrangements generating superpositions of macroscopically distinct coherent states may be adapted for precision phase-shift detection reaching the maximum sensitivity allowed by quantum physics (Heisenberg limit).
Quantum limits, nonseparable transformations, and nonlinear optics
(Physical review A, 2007) Luis Aina, Alfredo
We examine the relationship between nonseparable transformations and nonlinear optical processes, surpassing the Heisenberg limit in precision measurements.
Relative phase for a quantum field interacting with a two-level system
(Physical review A, 1997) Luis Aina, Alfredo; Sánchez Soto, Luis Lorenzo
Several quantum descriptions of the relative phase between an atomic dipole and a one-mode electromagnetic field are examined. Positive-operator measures for this variable are derived from dipole and field-phase formalisms. They are analyzed and compared with an operator defined by a polar decomposition. Some examples of time evolution are discussed.
Ensemble approach to coherence between two scalar harmonic light vibrations and the phase difference
(Physical review A, 2009) Luis Aina, Alfredo
We develop an approach to coherence between two scalar harmonic light vibrations derived from the ensemble interpretation of statistical optics. Coherence is presented as a statistical variable itself that turns out to be the phase difference between the two vibrations. This provides a natural and simple extension of second-order coherence to cover more complicated situations. This includes in a single formalism both classic and quantum light states, allowing the most accurate interferometric measurements, even if they are incoherent according to the standard second-order approach.
Practical schemes for the measurement of angular-momentum covariance matrices in quantum optics
(Physical review A, 2008) Rivas, Ángel; Luis Aina, Alfredo
We develop practical schemes for the measurement of the covariance matrix for intrinsic angular-momentum variables in quantum optics. We particularize this approach to two-beam polarimetry and interferometry, as well as to ensembles of two-level atoms interacting with classical fields. We show the practical advantages of noisy simultaneous measurements.
Operational approach to complementarity and duality relations
(Physical review A, 2004) Luis Aina, Alfredo
We present a fully operational and consistent approach to complementarity. In contrast to previous approaches, in this proposal the duality relations emerge exclusively from the outcomes of simultaneous measurements performed on every run of the experiment and under the same experimental conditions. This can be done without assuming any definite relationship between the measurement performed and the complementary observables being studied.
Zeno and anti-Zeno effects in multimode parametric down-conversion
(Physical review A, 2002) Luis Aina, Alfredo
We present a simple multimode analysis of the Zeno and anti-Zeno effects in spontaneous parametric down-conversion. In this process the input vacuum is an unstable state decaying into a reservoir of down-converted modes by emitting a pair of photons. We show that the Zeno and the anti-Zeno effects are two particular examples of quantum propagation depending on the effective spectrum of down-converted modes. We show that this evolution can be easily tailored on demand and that these quantum phenomena admit a very simple explanation in terms of standard interference concepts.
Polarization squeezing and nonclassical properties of light
(Physical review A, 2006) Luis Aina, Alfredo; Korolkova, Natalia
We formulate polarization uncertainty relations and polarization squeezing criteria in a SU(2) invariant manner. In this formulation the SU(2) coherent states are the only minimum uncertainty states. We show that polarization squeezing is a nonclassical property. We analyze the relation between polarization squeezing and other nonclassical properties such as entanglement and quadrature squeezing.
Phase properties of light propagating in a Kerr medium: Stokes parameters versus Pegg-Barnett predictions
(Physical review A, 1995) Luis Aina, Alfredo; Sánchez Soto, Luis Lorenzo; Tanaś, R.
The quantum theory of light propagation in a Kerr medium is applied to describe changes in the polarization state of light. A number of purely quantum effects arising during the propagation are analyzed. Stokes operators and Pegg-Barnett formalism are used to describe the evolution of the polarization ellipse. The predictions of these approaches are compared, showing some striking differences in the quantum regime of small photon numbers.
Metrological resolution and minimum uncertainty states in linear and nonlinear signal detection schemes
(Physical review A, 2009) Maldonado Mundo, Daniel; Luis Aina, Alfredo
We study the performance of linear and nonlinear optical schemes for the detection of weak signals for two classes of probe states. These are quadrature coherent squeezed states and the minimum uncertainty states of the generator of the transformation and the measured observable. Both for linear and nonlinear schemes we show that the generator-measurement minimum uncertainty states are far from being optimum, while the quadrature coherent squeezed states can reach maximum accuracy almost for the same amount of squeezing in both cases. The analysis is largely based on a suitable approximation treating the photon number as a continuous variable.