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We study the mini--superspace quantization of spatially homogeneous (Bianchi) cosmological universes sourced by a Dirac spinor field. The quantization of the homogeneous spinor leads to a finite-dimensional fermionic Hilbert space and…

General Relativity and Quantum Cosmology · Physics 2011-07-05 Thibault Damour , Philippe Spindel

We discuss several aspects of quantum field theory of a scalar field in a Friedmann universe, clarifying and highlighting several conceptual and technical issues. (A) We show that one can map the dynamics of (1) a massless scalar field in a…

General Relativity and Quantum Cosmology · Physics 2019-01-17 Kinjalk Lochan , Karthik Rajeev , Amit Vikram , T. Padmanabhan

Using properties of the determinant line bundle for a family of elliptic boundary value problems, we explain how the Fock space functor defines an axiomatic quantum field theory which formally models the Fermionic path integral. The 'sewing…

High Energy Physics - Theory · Physics 2009-10-31 Jouko Mickelsson , Simon Scott

Non-Hermitian Hamiltonians are relevant to describe the features of a broad class of physical phenomena, ranging from photonics and atomic and molecular systems to nuclear physics and mesoscopic electronic systems. An important question…

Mesoscale and Nanoscale Physics · Physics 2021-04-21 Ygor Pará , Giandomenico Palumbo , Tommaso Macrì

We present the Dirac Hamiltonian formalism for a pair of $1$-form fields with a topological-like potential coupled to first-order gravity in three-dimensional spacetime. By considering the complete phase space, we derive the full structure…

High Energy Physics - Theory · Physics 2026-01-13 Omar Rodríguez-Tzompantzi

Fermions are coupled to the Einstein-Cartan system in the canonical formulation, including the cosmological, the Barbero-Immirzi, and the non-minimal coupling constants. The resulting ten first-class constraints generate gauge…

General Relativity and Quantum Cosmology · Physics 2025-12-02 Erick I. Duque

Dirac particle represents a fundamental constituent of our nature. Simulation of Dirac particle dynamics by a controllable quantum system using quantum walks will allow us to investigate the non-classical nature of dynamics in its discrete…

Quantum Physics · Physics 2019-02-05 Arindam Mallick , Sanjoy Mandal , Anirban Karan , C. M. Chandrashekar

(1+1)-dimensional locally de Sitter Friedmann-Robertson-Walker cosmologies with compact spatial sections allow cosh, sinh and exponential evolution laws, each with a freely-specifiable spatial circumference parameter, and the value of this…

General Relativity and Quantum Cosmology · Physics 2024-01-19 Vladimir Toussaint , Jorma Louko

We analyze the spectrum of time observable in noncommutative cosmological model introduced in [5], defined by $(\rho, s=\frac 12)\,$ representation of the de Sitter group. We find that time has peculiar property: it is not self-adjoint, but…

High Energy Physics - Theory · Physics 2019-07-31 Maja Buric , Dusko Latas

We investigate the effective Dirac equation, corrected by merging two scenarios that are expected to emerge towards the quantum gravity scale. Namely, the existence of a minimal length, implemented by the generalized uncertainty principle,…

High Energy Physics - Theory · Physics 2020-08-18 J. M. Hoff da Silva , D. Beghetto , R. T. Cavalcanti , R. da Rocha

The action of the discrete symmetries on the scalar mode functions of the de Sitter spacetime is studied. The invariance with respect to a combination of discrete symmetries is put forward as a criterion to select a certain vacuum out of a…

General Relativity and Quantum Cosmology · Physics 2014-10-07 Ion I. Cotaescu , Gabriel Pascu

In the framework of algebraic quantum field theory we analyze the anomalous statistics exhibited by a class of automorphisms of the observable algebra of the two-dimensional free massive Dirac field, constructed by fermionic gauge group…

High Energy Physics - Theory · Physics 2015-06-26 Dario Salvitti

We study how to construct Dirac fermion defined on the honeycomb lattice in position space. Starting from the nearest neighbor interaction in tight binding model, we show that the Hamiltonian is constructed by kinetic term and second…

High Energy Physics - Lattice · Physics 2014-09-04 Masaki Hirotsu , Tetsuya Onogi , Eigo Shintani

The method of adiabatic invariants for time dependent Hamiltonians is applied to a massive scalar field in a de Sitter space-time. The scalar field ground state, its Fock space and coherent states are constructed and related to the particle…

General Relativity and Quantum Cosmology · Physics 2008-11-26 C. Bertoni , F. Finelli , G. Venturi

The spectrum of bound and scattering states of the one dimensional Dirac Hamiltonian describing fermions distorted by a static background built from two Dirac delta potentials is studied. A distinction will be made between mass-spike and…

Quantum Physics · Physics 2023-08-30 Lucía Santamaría-Sanz

We study a formal extension of the Dirac equation in the framework of a non-commutative two-sheeted space-time. It is shown that this approach naturally extends the classical Dirac theory by doubling the number of fermionic states, which…

High Energy Physics - Theory · Physics 2009-11-10 Fabrice Petit , Michael Sarrazin

The Hamiltonian formulation of general relativity (GR) is considered in finite space-time and a specific frame of reference given by the diffeo-invariant components of the Fock simplex in terms of the Dirac -- ADM variables. The evolution…

Astrophysics · Physics 2009-11-13 B. M. Barbashov , V. N. Pervushin , A. F. Zakharov , V. A. Zinchuk

We study the static patch of de Sitter space in the presence of a timelike boundary. We impose that the conformal class of the induced metric and the trace of the extrinsic curvature, $K$, are fixed at the boundary. We present the…

High Energy Physics - Theory · Physics 2025-01-29 Dionysios Anninos , Damián A. Galante , Chawakorn Maneerat

We present a fermion model characterized by an anticommuting-parameter shift symmetry. The Hamiltonian formulation exhibits a combination of first-class and second-class constraints. We derive the well-known Dirac equation by fixing the…

High Energy Physics - Theory · Physics 2023-06-30 Mauricio Valenzuela

Discrete fermionic and bosonic models for hyperbolic lattices have attracted significant attention across a range of fields since the experimental realization of hyperbolic lattices in metamaterial platforms, sparking the development of…

Mesoscale and Nanoscale Physics · Physics 2025-07-14 Ana Djordjević , Marija Dimitrijević Ćirić , Vladimir Juričić
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