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Mishkat Al Alvi

Publications and source records attributed to Mishkat Al Alvi.

6 recordsLinked to original sources
arXiv2019

Classicalization in Derivatively Coupled Scalar Field Theories: A Feasibility Study

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 $ϕ^4$ 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 energy two particle scattering, the ratios between the scattering amplitudes and the amplitude of classical structure formation in these two cases are an indicator of the feasibility of the classicalization process. From our calculation, it has been observed that with the increase of energy, the ratios of the relevant quantities between classicalizing and non-classicalizing theory actually decrease which is quite contrary to the expected behaviour if classicalization is supposed to self-unitarize certain class of theories beyond cut-off energy.

hep-th↗
arXiv2019

Modifications of the Page Curve from correlations within Hawking radiation

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.

hep-th↗
arXiv2017

Noncommutative scalar fields in compact spaces: quantisation and implications

In this paper we consider a two component scalar field theory, with noncommutativity in its conjugate momentum space. We quantize such a theory in a compact space with the help of dressing transformations and we reveal a significant effect of introducing such noncommutativity as the splitting of the energy levels of each individual mode that constitutes the whole system. We further compute the thermal partition function exactly with predicted deformed dispersion relations from noncommutative theories and compare the results with usual results. It is found that thermodynamic quantities in noncommutative models, irrespective of whether the model is more deformed in infrared/UV region, show deviation from standard results in high temperature region.

hep-th↗
arXiv2014

Does Considering Quantum Correlations Resolve the Information Paradox?

In this paper, we analyze whether quantum correlations between successive steps of evaporation can open any way to resolve the black hole information paradox. Recently a celebrated result in literature shows that `small' correction to leading order Hawking analysis fails to restore unitarity in black hole evaporation. We study a toy qubit model of evaporation allowing small quantum correlations between successive steps and verify the previous result. Then we generalize the concept of correction to Hawking state by relaxing the `smallness' condition. Our result generates a nontrivial upper and lower bound on change in entanglement entropy in the evaporation process. This gives us a quantitative measure of correction that would mathematically facilitate restoration of unitarity in black hole evaporation. We then investigate whether this result is compatible to the established physical constraints of unitary evolution of a state in a subsystem. We find that the generalized bound on entanglement entropy leads to significant deviation from Page curve. This leads us to agree with the recent claim in literature that no amount of correction in the form of Bell pair states would lead to any resolution to the information paradox.

hep-th↗
arXiv2014

Comments on Information Erasure in Black Hole

We analyze the Kim, Lee & 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.

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