Tachyonlike Excitations in Inverted Two-Level Media

Chiao, Raymond Y.; Kozhekin, A.; Kurizki, Gershon

doi:10.1103/physrevlett.77.1254

Cited by 81 publications

(54 citation statements)

References 18 publications

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“…Furthermore, many theoretical and few experimental work have implied that it is possible to obtain these abnormal velocities without the attenuation observed here [11], [13], [44]- [46], [48]. Therefore, it is natural to ask whether or not these abnormal behaviors are consistent with the requirements of special relativity, which demands no information can be transmitted faster than the speed of light in vacuum.…”

Section: Front and Information In Passive Mediamentioning

confidence: 98%

Abnormal wave propagation in passive media

Mojahedi

Malloy

Eleftheriades

et al. 2003

IEEE J. Select. Topics Quantum Electron.

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Abstract-Abnormal velocities in passive structures such as one-dimensional (1-D) photonic crystals and a slab having a negative index of refraction are discussed. In the case of 1-D photonic crystal, the frequency-and time-domain experiments for waves tuned to the bandgap of the photonic crystal demonstrate a positive group velocity exceeding the speed of light in vacuum (superluminal). In the case of a medium with negative index of refraction, our theoretical studies show that such a medium can support positive group and negative phase velocities (backward waves), as well as negative group and negative phase velocities. The meaning of superluminal group velocity and negative group velocity, or equally, positive superluminal group delay and negative group delay, are discussed. It is shown that despite their counterintuitive meaning there are no contradictions with the requirements of relativistic causality (Einstein causality). To clearly demonstrate this, the important subject of the "front" is reintroduced.Index Terms-Meta materials, negative group velocity, negative index of refraction, superluminal group velocity.

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Section: Front and Information In Passive Mediamentioning

confidence: 98%

Abnormal wave propagation in passive media

Mojahedi

Malloy

Eleftheriades

et al. 2003

IEEE J. Select. Topics Quantum Electron.

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“…On the (very interesting!) experimental side, see the intriguing papers [110]. Let us add here that, via quantum interference effects, it is possible to obtain dielectrics with refraction indices very rapidly varying as a function of frequency, also in three-level atomic systems, with almost complete absence of light absorption (i.e., with quantum induced transparency) [112].…”

Section: Appendix: a Glance At The Experi-mental State-of-the-artmentioning

confidence: 99%

Localized Waves: A Historical and Scientific Introduction

2007

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“…Chiao et al [1], [2], [3] have shown that certain "superluminal" effects are possible without violation of standard notions of Einstein causality, i.e., without conveying information faster than the velocity c of light in vacuum. Such effects have been demonstrated experimentally in optical tunneling [4], [5], [6] and in an electric circuit [7].…”

Section: Introductionmentioning

confidence: 99%

“…Questions have been raised about the validity of the latter prediction at the one-photon level, which would correspond to what CKK call an "optical tachyon" [1]. Aharonov, Reznik, and Stern (ARS) [8] have presented general arguments, based on the unitary evolution of the state vector, that "strongly questions the possibility that these systems may have tachyonlike quasiparticle excitations made up of a small number of photons."…”

Section: Introductionmentioning

confidence: 99%

Quantum noise and superluminal propagation

et al. 2000

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1 Abstract Causal "superluminal" effects have recently been observed and discussed in various contexts. The question arises whether such effects could be observed with extremely weak pulses, and what would prevent the observation of an "optical tachyon." Aharonov, Reznik, and Stern (ARS) [Phys. Rev. Lett. 81, 2190(1998 have argued that quantum noise will preclude the observation of a superluminal group velocity when the pulse consists of one or a few photons. In this paper we reconsider this question both in a general framework and in the specific example, suggested by Chiao, Kozhekin, and Kurizki [Phys. Rev. Lett. 77, 1254(1996], of off-resonant, short-pulse propagation in an optical amplifier. We derive in the case of the amplifier a signal-to-noise ratio that is consistent with the general ARS conclusions when we impose their criteria for distinguishing between superluminal propagation and propagation at the speed c. However, results consistent with the semiclassical arguments of CKK are obtained if weaker criteria are imposed, in which case the signal can exceed the noise without being "exponentially large." We show that the quantum fluctuations of the field considered by ARS are closely related to superfluorescence noise. More generally we consider the implications of unitarity for superluminal propagation and quantum noise and study, in addition to the complete and truncated wavepackets considered by ARS, the residual wavepacket formed by their difference. This leads to the conclusion that the noise is mostly luminal and delayed with respect to the superluminal signal. In the limit of a very weak incident signal pulse, the superluminal signal will be dominated by the noise part, and the signal-to-noise ratio will therefore be very small.

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Tachyonlike Excitations in Inverted Two-Level Media

Cited by 81 publications

References 18 publications

Abnormal wave propagation in passive media

Abnormal wave propagation in passive media

Localized Waves: A Historical and Scientific Introduction

Quantum noise and superluminal propagation

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