It has been suggested that a certain class of UV-incomplete quantum field theories can avoid unit... more It has been suggested that a certain class of UV-incomplete quantum field theories can avoid unitarity violation above the cut-off energy scale by forming classical configurations at a length scale much larger than the cut-off length. This phenomenon has been named classicalization and is characterized by a length scale called classicalization radius $r_*$ which increases with energy. It has been argued that scalar field theories with derivative self-interactions are likely candidate for UV-completetion by classicalization and are much likely to form classicalons compared to non-classicalizing theories like $\phi^4$ scalar field theory. To look further into this claim, in this paper 2 to N particle scattering amplitude, scattering cross-section and the amplitude of classical structure formation has been calculated and compared for a classicalizing and non-classicalizing theory. As the phenomenon of classicalization relies on creating a large number of low energy particles from high ...
We investigate quantum correlations between successive steps of black hole evaporation and invest... more We investigate quantum correlations between successive steps of black hole evaporation and investigate whether they might resolve the black hole information paradox. 'Small' corrections in various models were shown to be unable to restore unitarity. We study a toy qubit model of evaporation that allows small quantum correlations between successive steps and reaffirm previous results. Then, we relax the 'smallness' condition and find a nontrivial upper and lower bound on the entanglement entropy change during the evaporation process. This gives a quantitative measure of the size of the correction needed to restore unitarity. We find that these entanglement entropy bounds lead to a significant deviation from the expected Page curve.
The absence of consideration of subtle correlations in radiation process is the reason why Hawkin... more The absence of consideration of subtle correlations in radiation process is the reason why Hawking's semiclassical analysis is often criticized. There has been speculations that accounting for such quantum correlations would eventually invalidate Hawking's result that black hole evolution is non-unitary. However, it has been recently showed that considering small deviations from Hawking's analysis does not help significantly to bypass the information paradox-- the irreversible loss of information in the evolution of a black hole. This paper generalizes the above result by parametrization of the amount of deviation from Hawking's analysis that is required to resolve the paradox. With a more rigorous and non-trivial bound than that appeared in literature before, it is confirmed that information retrieval indeed requires `not-so-small' deviation from the Hawking state. In connection to this result, a previously proposed toy model of black hole evaporation is general...
We analyze the Kim, Lee and Lee model of information erasure by black holes and find contradictio... more We analyze the Kim, Lee and Lee model of information erasure by black holes and find contradictions with standard physical laws. We demonstrate that the erasure model leads to arbitrarily fast information erasure; the proposed physical interpretation of information freezing at the event horizon as observed by an asymptotic observer is problematic; and information erasure, whatever the process may be, near the black hole horizon leads to contradictions with quantum mechanics if Landauer's principle is assumed. The later part of the work demonstrates the significance of the "erasure entropy". We show that the erasure entropy is the mutual information between two subsystems.
2012 7th International Conference on Electrical and Computer Engineering, 2012
Hawking's argument about non-unitary evolution of black holes is often questioned on the ground t... more Hawking's argument about non-unitary evolution of black holes is often questioned on the ground that it doesn't acknowledge the quantum correlations in radiation process. However, recently it has been shown that adding 'small' correction to leading order Hawking analysis, accounting for the correlations, doesn't help to restore unitarity. This paper generalizes the bound on entanglement entropy by relaxing the 'smallness' condition and configures the parameters for possible recovery of information from an evaporating black hole. The new bound effectively puts an upper limit on increase in entanglement entropy. It also facilitates to relate the change in entanglement entropy to the amount of correction to Hawking state.
It has been suggested that a certain class of UV-incomplete quantum field theories can avoid unit... more It has been suggested that a certain class of UV-incomplete quantum field theories can avoid unitarity violation above the cut-off energy scale by forming classical configurations at a length scale much larger than the cut-off length. This phenomenon has been named classicalization and is characterized by a length scale called classicalization radius $r_*$ which increases with energy. It has been argued that scalar field theories with derivative self-interactions are likely candidate for UV-completetion by classicalization and are much likely to form classicalons compared to non-classicalizing theories like $\phi^4$ scalar field theory. To look further into this claim, in this paper 2 to N particle scattering amplitude, scattering cross-section and the amplitude of classical structure formation has been calculated and compared for a classicalizing and non-classicalizing theory. As the phenomenon of classicalization relies on creating a large number of low energy particles from high ...
We investigate quantum correlations between successive steps of black hole evaporation and invest... more We investigate quantum correlations between successive steps of black hole evaporation and investigate whether they might resolve the black hole information paradox. 'Small' corrections in various models were shown to be unable to restore unitarity. We study a toy qubit model of evaporation that allows small quantum correlations between successive steps and reaffirm previous results. Then, we relax the 'smallness' condition and find a nontrivial upper and lower bound on the entanglement entropy change during the evaporation process. This gives a quantitative measure of the size of the correction needed to restore unitarity. We find that these entanglement entropy bounds lead to a significant deviation from the expected Page curve.
The absence of consideration of subtle correlations in radiation process is the reason why Hawkin... more The absence of consideration of subtle correlations in radiation process is the reason why Hawking's semiclassical analysis is often criticized. There has been speculations that accounting for such quantum correlations would eventually invalidate Hawking's result that black hole evolution is non-unitary. However, it has been recently showed that considering small deviations from Hawking's analysis does not help significantly to bypass the information paradox-- the irreversible loss of information in the evolution of a black hole. This paper generalizes the above result by parametrization of the amount of deviation from Hawking's analysis that is required to resolve the paradox. With a more rigorous and non-trivial bound than that appeared in literature before, it is confirmed that information retrieval indeed requires `not-so-small' deviation from the Hawking state. In connection to this result, a previously proposed toy model of black hole evaporation is general...
We analyze the Kim, Lee and Lee model of information erasure by black holes and find contradictio... more We analyze the Kim, Lee and Lee model of information erasure by black holes and find contradictions with standard physical laws. We demonstrate that the erasure model leads to arbitrarily fast information erasure; the proposed physical interpretation of information freezing at the event horizon as observed by an asymptotic observer is problematic; and information erasure, whatever the process may be, near the black hole horizon leads to contradictions with quantum mechanics if Landauer's principle is assumed. The later part of the work demonstrates the significance of the "erasure entropy". We show that the erasure entropy is the mutual information between two subsystems.
2012 7th International Conference on Electrical and Computer Engineering, 2012
Hawking's argument about non-unitary evolution of black holes is often questioned on the ground t... more Hawking's argument about non-unitary evolution of black holes is often questioned on the ground that it doesn't acknowledge the quantum correlations in radiation process. However, recently it has been shown that adding 'small' correction to leading order Hawking analysis, accounting for the correlations, doesn't help to restore unitarity. This paper generalizes the bound on entanglement entropy by relaxing the 'smallness' condition and configures the parameters for possible recovery of information from an evaporating black hole. The new bound effectively puts an upper limit on increase in entanglement entropy. It also facilitates to relate the change in entanglement entropy to the amount of correction to Hawking state.
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Papers by Mishkat Alvi