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논문 자료실

Control of black hole evaporation

Ahn, Doyeol, Journal of high energy physics : JHEP v.2007 no.3 , 2007, pp.021 – 021 Contradiction between Hawking’s semi-classical arguments and the string theory on the evaporation of a black hole has been one of the most intriguing problems in fundamental physics. A final-state boundary condition inside the black hole was proposed by Horowitz and Maldacena to resolve this contradiction. We point out that the original Hawking effect can also be regarded as a separate boundary condition at the event horizon for this scenario. Here, we found that the change of the Hawking boundary condition may affect the information transfer from ... ...

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Hawking-Unruh effect and the entanglement of two-mode squeezed states in Riemannian space-time

Ahn, D. Physics letters: Av.366 no.3 , 2007, pp.202 – 205  We consider the system of free scalar field, which is assumed to be a two-mode squeezed state from an inertial point of view. This setting allows the use of entanglement measure for continuous variables, which can be applied to discuss free and bound entanglement from the point of view from non-inertial observer. ...

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Speedup of Grover’s search algorithm and closed timelike curves

Ki Hyuk Yee1, Jeongho Bang2, Paul M Alsing3, Warner A Miller4 and Doyeol Ahn6,1,4,5 Published 17 September 2020 • © 2020 IOP Publishing Ltd The quadratic reduction of query complexity of Grover’s search algorithm (GA), while significant, would not be enough to enjoy exponentially fast data searching in large-scale quantum computation. One of the ways to enhance the speedup in the framework of Grover’s algorithm is to employ a novel quantum operation, i.e., inversion against an unknown state; however, this is not possible at least in quantum theory. We thus extend the Grover algorithm assisted by closed timelike curves (CTCs), in which the unknown-state inversion is achievable ... ...

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