Quantum theory of time refraction

Mendonça, J. T.; Guerreiro, A.; Martins, Ana María Guerra

doi:10.1103/physreva.62.033805

Cited by 57 publications

(39 citation statements)

References 20 publications

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“…Using the continuity conditions for dielectric displacement and the magnetic induction fields [16,23] at time r = tu, the annihilation and creation operators for these modes can be related as…”

Section: Pacs Numbersmentioning

confidence: 99%

Production of bright entangled photons from moving optical boundaries

Guerreiro

Ferreira

Mendonça³

2011

Phys. Rev. A

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We discuss a mechanism of generating two separable beams of light with high degree of entanglement in momentum using a fast and sharp optical boundary. Three regimes of light generation are identified depending on the number of resonant interactions between the optical perturbation and the electromagnetic field. The intensity of the process is discussed in terms of the relevant physical parameters: variation of refractive index and apparent velocity of the optical boundary. Our results suggest a different class of generation entangled light robust against thermal degradation by exciting zero point fluctuations using parametric resonant optical modulations. PACS numbers:Introduction. Many of the theoretical schemes and experimental applications being proposed and developed in the context of Quantum Information (QI) (including quantum computation and information processing [1], teleportation [2], etc.) rely on the generation of entanglement between different quantum systems. Though entanglement can arise in nature even from the simplest interactions and even at high temperature [3,4], the degree of entanglement achieved is usually very small. An important exception are photons, which combined with their resilience to thermal effects, can be used, for example, to establish quantum communication at long-distances [5]. Till now, entangled photons are produced experimentally via parametric down conversion (PDC), which is in general a nonlinear process with small efficiency [6,7].

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Section: Pacs Numbersmentioning

confidence: 99%

Production of bright entangled photons from moving optical boundaries

Guerreiro

Ferreira

Mendonça³

2011

Phys. Rev. A

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“…Although this kind of particle production is believed to be dominant in the very early universe and is argued to be responsible for the initial seeds of inhomogeneity, which gave rise to the visible structures of the universe we live in [27][28][29], no experimental evidence of this has been observed so far. A similar effect is predicted to occur also in condensed matter systems [30] including Bose Einstein Condensates [31-33], rings of trapped ions [34], superfluid gases [35] and non-linear optics [36].There is a specific and independent body of literature concerned with the classical and quantum consequences of a homogeneous time variation of the real part of the refractive index alone under the name 'time refraction' [37,38]. Perhaps the first work in this general area is the work of Yablanovitch from 1989 [39].In this work, we consider the specific case of the optical non-linear Kerr effect in an ENZ material, such that a passing pulse of intense light modifies the refractive index of the background material on top of which vacuum fluctuations are propagating.…”

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confidence: 74%

“…There is a specific and independent body of literature concerned with the classical and quantum consequences of a homogeneous time variation of the real part of the refractive index alone under the name 'time refraction' [37,38]. Perhaps the first work in this general area is the work of Yablanovitch from 1989 [39].…”

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confidence: 99%

Spontaneous Photon Production in Time-Dependent Epsilon-Near-Zero Materials

et al. 2017

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Quantum field theory predicts that a spatially homogeneous but temporally varying medium will excite photon pairs out of the vacuum state. However, this important theoretical prediction lacks experimental verification due to the difficulty in attaining the required nonadiabatic and large amplitude changes in the medium. Recent work has shown that in epsilon-near-zero (ENZ) materials it is possible to optically induce changes of the refractive index of the order of unity, in femtosecond time scales. By studying the quantum field theory of a spatially homogeneous, time-varying ENZ medium, we theoretically predict photon-pair production that is up to several orders of magnitude larger than in non-ENZ time-varying materials. We also find that while in standard materials the emission spectrum depends on the time scale of the perturbation, in ENZ materials the emission is always peaked at the ENZ wavelength. These studies pave the way to technologically feasible observation of photon-pair emission from a time-varying background with implications for quantum field theories beyond condensed matter systems and with potential applications as a new source of entangled light. DOI: 10.1103/PhysRevLett.118.133904 Introduction.-Epsilon-near-zero (ENZ) materials are characterised by relative dielectric permittivity, whose real part, ε r , attains near-zero values around a given frequency ω ENZ [1,2]. A natural example of ENZ materials are commercially available transparent conducting oxides, e.g., indium-tin-oxide (ITO) or Al-doped ZnO (AZO), where ε r crosses 0 near the plasma frequency, whereas the imaginary part ε i is small. These materials are attracting attention for their rather remarkable properties, ranging from a geometric invariance of resonant structures to novel light propagation regimes and light emission geometries [2-10]. Recent work pioneered by Engheta et al. has started to focus on the quantum properties of these materials, including quantum emission in ENZ cavities and limitation or even complete suppression of vacuum modes [11,12].Alongside the fascinating linear optical properties of these materials, the nonlinear optical response exhibits an enhancement for frequencies close to ω ENZ [13][14][15][16][17][18][19]. In these first studies, the main enhancement mechanism of the nonlinearity is related to an enhancement of the z component (directed along the optical propagation axis) of the electrical field of the intense optical pump beam.An alternative nonlinear enhancement mechanism has also been reported that is based on the simple realization that in the ENZ region even a small change of permittivity Δε, induced by a third-order Kerr nonlinearity, can result in a

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“…there is a 'temporal boundary', then the frequency of light is modified. These ideas were then extended to account for quantum effects and, of particular interest in this context, included also the quantum vacuum and excitation of entangled photon pairs [18][19][20]. Over the last 10 years a number of papers have returned to the problem of light in moving media within the specific context of analogue gravity and with the explicit goal of evaluating the analogy between these systems and gravitational black holes [21][22][23][24][25][26][27][28][29][30][31][32].…”

Section: Analogue Gravity With Optics In Moving Mediamentioning

confidence: 98%

Laser pulse analogues for gravity and analogue Hawking radiation

Faccio

2012

Contemporary Physics

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Quantum theory of time refraction

Cited by 57 publications

References 20 publications

Production of bright entangled photons from moving optical boundaries

Production of bright entangled photons from moving optical boundaries

Spontaneous Photon Production in Time-Dependent Epsilon-Near-Zero Materials

Laser pulse analogues for gravity and analogue Hawking radiation

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