Black-hole lasers in Bose-Einstein condensates (2010)
Finazzi, Stefano, Parentani, Renaud
We consider elongated condensates that cross twice the speed of sound. In the absence of periodic boundary conditions, the phonon spectrum possesses a discrete and finite set of complex frequency...
From vacuum fluctuations across an event horizon to long distance correlations (2010)
We study the stress energy two-point function to show how short distance correlations across the horizon transform into correlations among asymptotic states, for the Unruh effect, and for black hole...
Black hole lasers, a mode analysis (2009)
Coutant, Antonin, Parentani, Renaud
We show that the black hole laser effect discovered by Corley & Jacobson should be described in terms of frequency eigenmodes that are spatially bound. The spectrum contains a discrete and finite set...
Black-hole radiation in Bose-Einstein condensates (2009)
Macher, Jean, Parentani, Renaud
We study the phonon fluxes emitted when the condensate velocity crosses the speed of sound, i.e., in backgrounds which are analogous to that of a black hole. We focus on elongated one dimensional...
Black/White hole radiation from dispersive theories (2009)
Macher, Jean, Parentani, Renaud
We study the fluxes emitted by black holes when using dispersive field theories. We work with stationary one dimensional backgrounds which are asymptotically flat on both sides of the horizon. The...
Inflationary Spectra from Lorentz Violating Dissipative Models (2008)
Adamek, Julian, Campo, David, Niemeyer, Jens C., Parentani, Renaud
The sensitivity of inflationary spectra to initial conditions is addressed in the context of a phenomenological model that breaks Lorentz invariance by dissipative effects above some threshold energy...
Horizon surface gravity as 2d geodesic expansion (2008)
Jacobson, Ted, Parentani, Renaud
The surface gravity of any Killing horizon, in any spacetime dimension, can be interpreted as a local, two-dimensional expansion rate seen by freely falling observers when they cross the horizon. Any...
Decoherence and entropy of primordial fluctuations II. The entropy budget (2008)
Campo, David, Parentani, Renaud
We calculate the entropy of adiabatic perturbations associated with a truncation of the hierarchy of Green functions at the first non trivial level, i.e. in a self-consistent Gaussian approximation....
Decoherence and entropy of primordial fluctuations. I: Formalism and interpretation (2008)
Campo, David, Parentani, Renaud
We propose an operational definition of the entropy of cosmological perturbations based on a truncation of the hierarchy of Green functions. The value of the entropy is unambiguous despite gauge...
Signatures of trans-Planckian dispersion in inflationary spectra (2008)
Macher, Jean, Parentani, Renaud
The primordial spectra are calculated using dispersion relations which deviate from the relativistic one above a certain energy scale Lambda. We determine the properties of the leading modifications...
Confronting the trans-Planckian question of inflationary cosmology with dissipative effects (2007)
We provide a class of QFTs which exhibit dissipation above a threshold energy, thereby breaking Lorentz invariance. Unitarity is preserved by coupling the fields to additional degrees of freedom...
A Primer for Black Hole Quantum Physics (2007)
Brout, Robert, Massar, Serge, Parentani, Renaud, Spindel, Philippe
The mechanisms which give rise to Hawking radiation are revealed by analyzing in detail pair production in the presence of horizons. In preparation for the black hole problem, three preparatory...
Constructing QFT's wherein Lorentz Invariance is broken by dissipative effects in the UV (2007)
There has been a recent interest in considering Quantum Field Theories in which Lorentz Invariance is broken in the UV sector. However attention has been mostly limited to dispersive theories. In...
Damped Corrections to Inflationary Spectra from a Fluctuating Cutoff (2007)
Campo, David, Niemeyer, Jens, Parentani, Renaud
We reconsider trans-Planckian corrections to inflationary spectra by taking into account a physical effect which has been overlooked and which could have important consequences. We assume that the...
Black hole entanglement entropy regularized in a freely falling frame (2007)
Jacobson, Ted, Parentani, Renaud
We compute the black hole horizon entanglement entropy S_E for a massless scalar field, first with a hard cutoff and then with high frequency dispersion, both imposed in a frame that falls freely...
Inflationary spectra and violations of Bell inequalities (2007)
Campo, David, Parentani, Renaud
In spite of the macroscopic character of the primordial fluctuations, the standard inflationary distribution (that obtained using linear mode equations) exhibits inherently quantum properties, that...
Inflationary spectra and partially decohered distributions (2007)
Campo, David, Parentani, Renaud
It is generally expected that decoherence processes will erase the quantum properties of the inflationary primordial spectra. However, given the weakness of gravitational interactions, one might end...
Quantum correlations in inflationary spectra and violation of Bell inequalities (2007)
Campo, David, Parentani, Renaud
In spite of the macroscopic character of the fluctuation amplitudes, we show that the standard inflationary distribution of primordial density fluctuations still exhibits inherently quantum...
Damped Corrections to Inflationary Spectra from a Fluctuating Cutoff (2007)
Campo, David, Niemeyer, Jens, Parentani, Renaud
We reconsider trans-Planckian corrections to inflationary spectra by taking into account a physical effect which has been overlooked and which could have important consequences. We assume that the...
Beyond the semi-classical description of black hole evaporation (2007)
In the semi-classical treatment, i.e. in a classical black hole geometry, Hawking quanta emerge from trans-Planckian configurations because of scale invariance. There is indeed no scale to stop the...
Black hole entanglement entropy regularized in a freely falling frame (2007)
Jacobson, Ted, Parentani, Renaud
We compute the black hole horizon entanglement entropy S_E for a massless scalar field, first with a hard cutoff and then with high frequency dispersion, both imposed in a frame that falls freely...
What did we learn from studying acoustic black holes ? (2007)
The study of acoustic black holes has been undertaken to provide new insights about the role of high frequencies in black hole evaporation. Because of the infinite gravitational redshift from the...
Space-time correlations in inflationary spectra, a wave packet analysis (2006)
Campo, David, Parentani, Renaud
The inflationary mechanism of mode amplification predicts that the state of each mode with a given wave vector is correlated to that of its partner mode with the opposite vector. This implies...
Space-time correlations within pairs produced during inflation, a wave-packet analysis (2006)
Campo, David, Parentani, Renaud
In homogeneous universes the propagation of quantum fields gives rise to pair creation of quanta with opposite momenta. When computing expectation values of operators, the correlations between these...
Quantum correlations in inflationary spectra and violation of bell inequalities (2005)
In spite of the macroscopic character of the fluctuation amplitudes, we show that the standard inflationary distribution of primordial density fluctuations still exhibits inherently quantum...
Quantum correlations in inflationary spectra and violation of Bell inequalities (2005)
Campo, David, Parentani, Renaud
In spite of the macroscopic character of the fluctuation amplitudes, we show that the standard inflationary distribution of primordial density fluctuations still exhibits inherently quantum...
Inflationary spectra and violations of Bell inequalities (2005)
Campo, David, Parentani, Renaud
In spite of the macroscopic character of the primordial fluctuations, the standard inflationary distribution (that obtained using linear mode equations) exhibits inherently quantum properties, that...
Inflationary spectra and partially decohered distributions (2005)
Campo, David, Parentani, Renaud
It is generally expected that decoherence processes will erase the quantum properties of the inflationary primordial spectra. However, given the weakness of gravitational interactions, one might end...
Inflationary spectra, decoherence, and two-mode coherent states (2004)
Campo, David, Parentani, Renaud
We re-examine the question of the entropy stored in the distribution of primordial density fluctuations. To this end we make use of two-mode coherent states. These states incorporate the isotropy of...
Propagation in a thermal graviton background (2004)
Arteaga Barriel, Daniel, Parentani, Renaud
It is well known that radiative corrections evaluated in nontrivial backgrounds lead to effective dispersion relations which are not Lorentz invariant. Since gravitational interactions increase with...
Space-time correlations in inflationary spectra, a wave packet analysis (2003)
Campo, David, Parentani, Renaud
The inflationary mechanism of mode amplification predicts that the state of each mode with a given wave vector is correlated to that of its partner mode with the opposite vector. This implies...
Propagation in a thermal graviton background (2003)
Arteaga, Daniel, Parentani, Renaud, Verdaguer, Enric
It is well known that radiative corrections evaluated in nontrivial backgrounds lead to effective dispersion relations which are not Lorentz invariant. Since gravitational interactions increase with...
Jacobson, Ted, Parentani, Renaud
Although the laws of thermodynamics are well established for black hole horizons, much less has been said in the literature to support the extension of these laws to more general settings such as an...
Space-time correlations within pairs produced during inflation, a wave-packet analysis (2003)
Campo, David, Parentani, Renaud
In homogeneous universes the propagation of quantum fields gives rise to pair creation of quanta with opposite momenta. When computing expectation values of operators, the correlations between these...
What did we learn from studying acoustic black holes ? (2002)
The study of acoustic black holes has been undertaken to provide new insights about the role of high frequencies in black hole evaporation. Because of the infinite gravitational redshift from the...
The interpretation of the solutions of the Wheeler De Witt equation (1997)
We extract transition amplitudes among matter constituents of the universe from the solutions of the Wheeler De Witt equation. The physical interpretation of these solutions is then reached by an...
Thermodynamics of a black hole in a cavity (1994)
Parentani, Renaud, Katz, Joseph, Okamoto, Isao
We present a unified thermodynamical description of the configurations consisting on self-gravitating radiation with or without a black hole. We compute the thermal fluctuations and evaluate where...
The Internal Geometry of an Evaporating Black Hole (1994)
Parentani, Renaud, Piran, Tsvi
We present a semi-classical model for the formation and evaporation of a four dimensional black hole. We solve the equations numerically and obtain solutions describing the entire the space-time...
The Internal Geometry of an Evaporating Black Hole (1994)
Black Hole, Renaud Parentani, Tsvi Piran
We present a semi-classical model for the formation and evaporation of a four dimensional black hole. We solve the equations numerically and obtain solutions describing the entire the space-time...