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Lissa de Souza Campos

Bio: Lissa de Souza Campos is an academic researcher from Istituto Nazionale di Fisica Nucleare. The author has contributed to research in topics: Boundary value problem & Robin boundary condition. The author has an hindex of 1, co-authored 4 publications receiving 6 citations.

Papers
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TL;DR: In this article, the authors show that the anti-Hawking effect does not occur on a four-dimensional massless hyperbolic topological black hole with a ground state and a thermal state.
Abstract: On an $n$-dimensional, massless, topological black hole with hyperbolic sections, we construct the two-point function both of a ground state and of a thermal state for a real, massive, free scalar field arbitrarily coupled to scalar curvature and endowed with Robin boundary conditions at conformal infinity. These states are used to compute the response of an Unruh-DeWitt detector coupled to them for an infinite proper time interval along static trajectories. As an application, we focus on the massless conformally coupled case, and we show, numerically, that the anti-Hawking effect, which is manifest on the three-dimensional case, does not occur if we consider a four-dimensional massless hyperbolic black hole. On the one hand, we argue that this result is compatible with what happens in the three- and four-dimensional Minkowski spacetime, while, on the other hand, we stress that it generalizes existing results concerning the anti-Hawking effect on black hole spacetimes.

18 citations

Journal ArticleDOI
TL;DR: In this paper, thermal effects on a naked singularity and its relation with boundary conditions were studied. But the transition rate was not analyzed for the particular cases of massless minimally or conformally coupled fields at finite temperature.
Abstract: Within quantum field theory on a global monopole spacetime, we study thermal effects on a naked singularity and its relation with boundary conditions. We first obtain the two-points functions for the ground state and for thermal states of a massive, arbitrarily-coupled, free scalar field compatible with Robin boundary conditions at the singularity. We then probe these states using a static Unruh-Dewitt particle detector. The transition rate is analyzed for the particular cases of massless minimally or conformally coupled fields at finite temperature. To interpret the detector's behavior, we compute the thermal contribution to the ground-state fluctuations and to the energy density. We verify that the behavior of the transition rate, the fluctuations and the energy density are closely intertwined. In addition, we find that these renormalized quantities remain finite at the singularity for, and only for, Dirichlet boundary condition.
Journal ArticleDOI
TL;DR: In this article , the two-point correlation functions for ground and thermal states of a real Klein-Gordon field admitting generalized (γ,v)-boundary conditions were constructed on PAdS2×S2.
Posted Content
TL;DR: In this paper, thermal effects on a naked singularity and its relation with boundary conditions were studied. But the transition rate was not analyzed for the particular cases of massless minimally or conformally coupled fields at finite temperature.
Abstract: Within quantum field theory on a global monopole spacetime, we study thermal effects on a naked singularity and its relation with boundary conditions. We first obtain the two-points functions for the ground state and for thermal states of a massive, arbitrarily-coupled, free scalar field compatible with Robin boundary conditions at the singularity. We then probe these states using a static Unruh-Dewitt particle detector. The transition rate is analyzed for the particular cases of massless minimally or conformally coupled fields at finite temperature. To interpret the detector's behavior, we compute the thermal contribution to the ground-state fluctuations and to the energy density. We verify that the behavior of the transition rate, the fluctuations and the energy density are closely intertwined. In addition, we find that these renormalized quantities remain finite at the singularity for, and only for, Dirichlet boundary condition.
Posted Content
TL;DR: In this paper, the authors considered a real Klein-Gordon field and split the equation of motion into a radial and an angular component, and discussed under which conditions on the underlying parameters, the radial equation boundary conditions of Robin type and whether bound state solutions do occur.
Abstract: On a class of four-dimensional Lifshitz spacetimes with critical exponent $z=2$, including a hyperbolic and a spherical Lifshitz topological black hole, we consider a real Klein-Gordon field. Using a mode-decomposition, we split the equation of motion into a radial and into an angular component. As first step, we discuss under which conditions on the underlying parameters, we can impose to the radial equation boundary conditions of Robin type and whether bound state solutions do occur. Subsequently, we show that, whenever bound states are absent, one can associate to each admissible boundary condition a ground and a KMS state whose associated two-point correlation function is of local Hadamard form.

Cited by
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Journal ArticleDOI
TL;DR: In this article, the transition rate of an Unruh-DeWitt detector coupled both to a ground state and to a KMS state of a massless, conformally coupled scalar field on a static BTZ black hole with Robin boundary conditions is computed.

17 citations

BookDOI
01 Jan 2020
TL;DR: The well-posedness of boundary value problems for elastic cusped prismatic shells in the N -th approximation of I.Vekua’s hierarchical models under (all reasonable) boundary conditions at the cusPed edge and given displacements at the non-cusped edge is studied.
Abstract: We study the well-posedness of boundary value problems for elastic cusped prismatic shells in the N -th approximation of I.Vekua’s hierarchical models under (all reasonable) boundary conditions at the cusped edge and given displacements at the non-cusped edge and stresses at the upper and lower faces of the shell. Mathematics Subject Classification 2000. Primary 74K20; Secondary 35J70

14 citations

Journal ArticleDOI
TL;DR: In this article , a tripartite entanglement harvesting protocol with three Unruh-DeWitt detectors adiabatically interacting with a quantum scalar field is presented.
Abstract: We analyze a tripartite entanglement harvesting protocol with three Unruh-DeWitt detectors adiabatically interacting with a quantum scalar field. We consider linear, equilateral triangular, and scalene triangular configurations for the detectors. We find that, under the same parameters, more entanglement can be extracted in the linear configuration than the equilateral one, consistent with single instantaneous switching results. No bipartite entanglement is required to harvest tripartite entanglement. Furthermore, we find that tripartite entanglement can be harvested even if one detector is at larger spacelike separations from the other two than in the corresponding bipartite case. We also find that for small detector separations bipartite correlations become larger than tripartite ones, leading to an apparent violation of the Coffman-Kundu-Wootters (CKW) inequality. We show that this is not a consequence of our perturbative expansion but that it instead occurs because the harvesting qubits are in a mixed state.

9 citations

Posted Content
TL;DR: In this article, the effects of rotation on the weak and strong anti-Hawking effects for an Unruh-DeWitt detector orbiting a BTZ black hole in the co-rotating frame were investigated.
Abstract: In both flat and curved spacetimes, there are weak and strong versions of the anti-Unruh/anti-Hawking effects, in which the KMS field temperature is anti-correlated with the response of a detector and its inferred temperature. We investigate for the first time the effects on the weak and strong anti-Hawking effects for an Unruh-DeWitt detector orbiting a BTZ black hole in the co-rotating frame. We find that rotation can significantly amplify the strength of the weak anti-Hawking effect, whereas it can either amplify or reduce the strength of the strong anti-Hawking effect depending on boundary conditions. For the strong anti-Hawking effect, we find a non-monotonic relationship between the angular momentum and detector temperature for each boundary condition. In addition, we note that the weak anti-Hawking effect is independent of a changing AdS length, while a longer AdS length increases the temperature range of the strong anti-Hawking effect.

8 citations

Journal ArticleDOI
TL;DR: In this paper , the effects of rotation on the weak and strong anti-Hawking effects were investigated for an Unruh-DeWitt detector orbiting a Banados-Teitelboim-Zanelli black hole in the corotating frame.
Abstract: In both flat and curved spacetimes, there are weak and strong versions of the anti-Unruh/anti-Hawking effects, in which the Kubo-Martin-Schwinger field temperature is anticorrelated with the response of a detector and its inferred temperature. We investigate for the first time the effects on the weak and strong anti-Hawking effects for an Unruh-DeWitt detector orbiting a Banados-Teitelboim-Zanelli black hole in the corotating frame. We find that rotation can significantly amplify the strength of the weak anti-Hawking effect, whereas it can either amplify or reduce the strength of the strong anti-Hawking effect depending on boundary conditions. For the strong anti-Hawking effect, we find a nonmonotonic relationship between the angular momentum and detector temperature for each boundary condition. In addition, we note that the weak anti-Hawking effect is independent of a changing AdS length, while a longer AdS length increases the temperature range of the strong anti-Hawking effect.

7 citations