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O. Garcia

Publications and source records attributed to O. Garcia.

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Entropy-Deformed Hamiltonian Dynamics of Schwarzschild Black Holes: A Superstatistical Approach

We study the effective dynamics of the Schwarzschild black hole interior by introducing entropic deformations derived from generalized superstatistical entropies $S_{+}$ and $S_{-}$. The resulting modified Hamiltonians $\bar{H}_{\pm}$, formulated in Ashtekar--Barbero variables, encode quantum gravity-inspired corrections that become significant near the Planck scale. Analytical solutions show that these corrections regularize the classical singularity, replacing it with a finite anisotropic core characterized by bounded canonical variables and a minimal internal area. For $S_{-}$ ($\alpha_{-} > 0$), curvature invariants remain finite, yielding a completely regular interior, whereas $S_{+}$ ($\alpha_{+} < 0$) leads to a localized region of high curvature associated with a cigar-like throat. The interior and exterior geometries are thus connected through this high-curvature region, indicating that the classical singularity is replaced by an entropic transition layer. These features reproduce loop quantum gravity phenomenology without invoking polymer discretization.

gr-qc

A Bose-Einstein condensate interferometer with macroscopic arm separation

A Michelson interferometer using Bose-Einstein condensates is demonstrated with coherence times of up to 44 ms and arm separations up to 0.18 mm. This arm separation is larger than that observed for any previous atom interferometer. The device uses atoms weakly confined in a magnetic guide and the atomic motion is controlled using Bragg interactions with an off-resonant standing wave laser beam.

cond-mat.other

A Time-Orbiting Potential Trap for Bose-Einstein Condensate Interferometry

We describe a novel atom trap for Bose-Einstein condensates of 87Rb to be used in atom interferometry experiments. The trap is based on a time-orbiting potential waveguide. It supports the atoms against gravity while providing weak confinement to minimize interaction effects. We observe harmonic oscillation frequencies omega_x, omega_y, omega_z as low as 2 pi times (6.0,1.2,3.3) Hz. Up to 2 times 10^4 condensate atoms have been loaded into the trap, at estimated temperatures as low as 850 pK. We anticipate that interferometer measurement times of 1 s or more should be achievable in this device.

cond-mat.other