Hawking radiation from 'phase horizons' in laser filaments?

Belgiorno et al have reported on experiments aiming at the detection of (the analogue of) Hawking radiation using laser filaments [F. Belgiorno et al, Phys. Rev. Lett. 105, 203901 (2010)]. They sent intense focused Bessel pulses into a non-linear dielectric medium in order to change its refractive index via the Kerr effect and saw creation of photons orthogonal to the direction of travel of the pluses. Since the refractive index change in the pulse generated a "phase horizon" (where the phase velocity of these photons equals the pulse speed), they concluded that they observed the analogue of Hawking radiation. We study this scenario in a model with a phase horizon and a phase velocity very similar to that of their experiment and find that the effective metric does not quite correspond to a black hole. The photons created in this model are not due to the analogue of black hole evaporation but have more similarities to cosmological particle creation. Nevertheless, even this effect cannot explain the observations -- unless the pulse has significant small scale structure in both the longitudinal and transverse dimensions.

[1]  S. Robertson.  The theory of Hawking radiation in laboratory analogues , 2012, 1508.02569.

[2]  I. Carusotto,et al.  Kinematic study of the effect of dispersion in quantum vacuum emission from strong laser pulses , 2012, 1204.3603.

[3]  M. Visser,et al.  Quantum vacuum radiation in optical glass , 2011, 1111.0214.

[4]  V. G. Sala,et al.  Experimental evidence of analogue Hawking radiation from ultrashort laser pulse filaments , 2011 .

[5]  W. Unruh,et al.  Comment on "Hawking radiation from ultrashort laser pulse filaments". , 2010, Physical review letters.

[6]  V. G. Sala,et al.  Hawking radiation from ultrashort laser pulse filaments. , 2010, Physical review letters.

[7]  V. G. Sala,et al.  Spacetime geometries and light trapping in travelling refractive index perturbations , 2010, 1006.1097.

[8]  D. Faccio,et al.  Dielectric black holes induced by a refractive index perturbation and the Hawking effect , 2010, 1003.4150.

[9]  V. G. Sala,et al.  Quantum radiation from superluminal refractive-index perturbations. , 2009, Physical review letters.

[10]  U. Leonhardt,et al.  Fiber-Optical Analog of the Event Horizon , 2007, Science.

[11]  W. Unruh,et al.  Hawking radiation in an electromagnetic waveguide? , 2004, Physical review letters.

[12]  R. Schutzhold,et al.  On slow light as a black hole analogue , 2003, gr-qc/0303028.

[13]  U. Leonhardt.  A laboratory analogue of the event horizon using slow light in an atomic medium , 2002, Nature.

[14]  U. Leonhardt.  Quantum catastrophe of slow light , 2001, physics/0111058.

[15]  G. Soff,et al.  Dielectric black hole analogs. , 2001, Physical review letters.

[16]  Leonhardt,et al.  Leonhardt and piwnicki reply: , 2000, Physical review letters.

[17]  Visser,et al.  Comment on "Relativistic effects of light in moving media with extremely low group velocity" , 2000, Physical review letters.

[18]  Leonhardt,et al.  Relativistic effects of light in moving media with extremely low group velocity , 1999, Physical review letters.

[19]  R. Schutzhold,et al.  QUANTUM RADIATION IN EXTERNAL BACKGROUND FIELDS , 1998, quant-ph/9801035.

[20]  P. N. Butcher,et al.  The Elements of Nonlinear Optics , 1990 .

[21]  I. Bialynicki-Birula,et al.  Space–time description of squeezing , 1987 .

[22]  W. Unruh.  Experimental black hole evaporation , 1981 .

[23]  S. Hawking,et al.  Black hole explosions? , 1974, Nature.

[24]  J. Hopfield.  a Quantum-Mechanical Theory of the Contribution of Excitons to the Complex Dielectric Constant of Crystals. , 1958 .

[25]  Erwin Schro¨dinger.  The proper vibrations of the expanding universe , 1939 .

[26]  S. Hawking.  Particle creation by black holes , 1975 .

[27]  W. Gordon,et al.  Zur Lichtfortpflanzung nach der Relativitätstheorie , 1923 .