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Ivana Đorđević

Publications and source records attributed to Ivana Đorđević.

3 recordsLinked to original sources

Bell nonlocality from twisted statistics

We investigate Bell correlations for a free real quantum scalar field on the noncommutative Moyal plane. Although the free field dynamics and the one-particle sector remain unchanged, the deformation enters through twisted multiparticle statistics and its Fock-space dressing representation. A classical external source coupled locally to the twist-dressed quantum field prepares coherent superpositions of momentum-pair configurations propagating toward two spacelike-separated laboratories. The momentum-dependent twist phases are generally nonfactorizable and generate entanglement between the corresponding wave-packet modes. We show that suitable local mode measurements lead to a violation of the CHSH Bell inequality. The resulting correlations provide an operational probe of the noncommutative structure encoded in the multiparticle sector of the quantum field.

quant-ph↗

Entangled quantum clocks as operational probes of spacetime curvature

Building on the framework developed by Perche [Phys. Rev. D 106, 025018 (2022)], we study two localized nonrelativistic quantum particles propagating along timelike geodesics in a curved spacetime background. Each particle is coupled to a quantum clock that operationally records the time spent in a prescribed spatial region. We compute the covariance of the resulting time observables for separable and entangled two-particle states, comparing flat and curved backgrounds. We then reformulate the protocol as a Bell-like experiment and show that the Bell parameter can acquire a curvature-induced correction. In particular, a protocol calibrated to saturate the classical bound in flat spacetime can be driven above this bound in curved spacetime for entangled states. We focus on two-dimensional curved backgrounds in which the local tidal term induces an effective harmonic potential in the Fermi-frame description. Our results show that spacetime curvature can modify operationally defined quantum correlations and suggest entangled quantum clocks as probes of spacetime curvature.

quant-ph↗

The role of torsion in holographic conductivity

Generalizing the usual setup for holographic duality, where bulk spacetime is described by pseudo-Riemannian geometry, we consider a Riemann-Cartan bulk with non-trivial torsion as a background for an electromagnetic gauge field dual to $U(1)$ boundary current. Working in the probe limit, we explore how the bulk torsion, which induces spin current at the boundary, affects the electric conductivity of the boundary theory. We consider standard types of non-minimal couplings between torsion and the electromagnetic field found in the literature, and the results indicate that these torsion couplings are more suitable candidates, compared to the common minimal coupling regime, for a holographic description of the existing experimental findings regarding conductivity.

hep-th↗