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We provide an estimate on the absolute values of the emission rate of photon pairs produced by spontaneous parametric down conversion in a bulk crystal when all interacting fields are in single transverse Gaussian modes. Both collinear and…

Quantum Physics · Physics 2008-04-29 Alexander Ling , Antia Lamas-Linares , Christian Kurtsiefer

We present a novel yet simple approach to produced multiple entangled photon pairs through spontaneous parametric downconversion. We have developed Gaussian masks to subdivide the pump beam before passing it through a nonlinear medium. In…

Quantum Physics · Physics 2021-05-13 Phillip Heitert , Finn Buldt , Pascal Bassene , Moussa N'Gom

Thermo Field Dynamics for inhomogeneous systems is generalized to quantum fields with a continuous single-particle mass spectrum. The modification of the hamiltonian in states with a local thermal Bogoliubov symmetry is used to calculate…

Nuclear Theory · Physics 2009-10-22 P. A. Henning

Non-equilibrium thermodynamics of the driven resonant level model is studied using numerical simulations based on the driven Liouville von-Neumann formalism. The approach is first validated against recently obtained analytical results for…

Mesoscale and Nanoscale Physics · Physics 2019-10-08 Annabelle Oz , Oded Hod , Abraham Nitzan

We develop a local realist analysis of parametric down conversion, based on the recognition that the pump field, instead of down converting spontaneously, does so through its nonlinear coupling with a real zeropoint, or "vacuum"…

Quantum Physics · Physics 2007-05-23 Trevor W. Marshall

We experimentally investigate the parametric down-conversion process in a nonlinear bulk crystal, driven by two non-collinear pump modes. The experiment shows the emergence of bright hot-spots in modes shared by the two pumps, in analogy…

Quantum Physics · Physics 2020-12-30 Ottavia Jedrkiewicz , Erica Invernizzi , Enrico Brambilla , Alessandra Gatti

We study analytically the photon generation from vacuum due to the Dynamical Casimir effect in a cavity with a two-level atom, prepared initially in an arbitrary pure state. Performing small unitary transformations we obtain closed…

Quantum Physics · Physics 2012-01-19 A. V. Dodonov , V. V. Dodonov

The coupling of two-level quantum systems to the thermal environment is a fundamental problem, with applications ranging from qubit state preparation to spin models. However, for the elementary problem of the thermodynamics of an ensemble…

Quantum Gases · Physics 2025-10-29 Christian Kurtscheid , Andreas Redmann , Frank Vewinger , Julian Schmitt , Martin Weitz

A rigorous description of volume and surface spontaneous parametric down-conversion in 1D nonlinear layered structures is developed considering exact continuity relations for the fields' amplitudes at the boundaries. The nonlinear process…

Quantum Physics · Physics 2017-04-26 D. Javurek , J. Perina

We explore the advantages offered by twin light beams produced in parametric down-conversion for precision measurement. The symmetry of these bipartite quantum states, even under losses, suggests that monitoring correlations between the…

Quantum Physics · Physics 2010-07-20 Hugo Cable , Gabriel A. Durkin

Using the Dirac-Frenkel variational principle, a time-dependent description of the dynamics of a two-level system coupled to a bosonic bath is formulated. The method is applied to the case of a gas of cold atoms adsorbing to an elastic…

Mesoscale and Nanoscale Physics · Physics 2024-12-04 Dennis P. Clougherty

Measurement of photon-number statistics of fields composed of photon pairs generated in spontaneous parametric downcoversion pumped by strong ultrashort pulses is described. Final detection quantum efficiencies, noises as well as possible…

Quantum Physics · Physics 2007-05-23 J. Perina , O. Haderka , M. Hamar

Spectro-temporal modes of light can be exploited for the generation of high-dimensional Gaussian quantum states. Such states are at the basis of continuous variable quantum information protocols where they have to support mode-selective…

We present a detailed account of the two-photon states generated by SPDC in both type I and type II phase matching, including the effects of anisotropy of the nonlinear medium and the frequency spread of the down-converted fields. Accurate…

Quantum Physics · Physics 2008-07-01 A. G. da Costa Moura , W. A. T. Nogueira , S. P. Walborn , C. H. Monken

Photon-added coherent states have been realized in optical parametric down-conversion by Zavatta {\em et al} [Science 306 (2004) 660-662]. In this report, it is established that the states generated in the process are {\em ideal}…

Quantum Physics · Physics 2015-05-27 S. Sivakumar

The dynamics of an initially excited two-level atom in a lossy cavity is studied by using the quantum trajectory method. Unwanted losses are included, such as photon absorption and scattering by the cavity mirrors and spontaneous emission…

Quantum Physics · Physics 2008-04-18 C. Di Fidio , W. Vogel , M. Khanbekyan , D. -G. Welsch

We show that the transfer of the angular spectrum of the pump beam to the two-photon state in spontaneous parametric down-conversion enables the generation of entangled Hermite-Gaussian modes. We derive an analytical expression for the…

Quantum Physics · Physics 2009-11-10 S. P. Walborn , S. Pádua , C. H. Monken

We address the pair of conjugated field modes obtained from parametric-downconversion as a convenient system to analyze the quantum-classical transition in the continuous variable regime. We explicitly evaluate intensity correlations,…

The multiphoton states generated by high-gain spontaneous parametric down-conversion (SPDC) in presence of large losses are investigated theoretically and experimentally. The explicit form for the two-photon output state has been found to…

The purpose of this paper is to study the interaction between a two-level system and two continuous-mode photons. Two scenarios are investigated: Case 1, how a two-level system changes the pulse shapes of two input photons propagating in a…

Quantum Physics · Physics 2019-10-14 Zhiyuan Dong , Guofeng Zhang , Nina H. Amini