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A practical computation method to find the eigenvalues and eigenspinors of quantum mechanical Hamiltonian is presented. The method is based on reduction of the eigenvalue equation to well known geometric algebra rotor equation and,…

Mathematical Physics · Physics 2015-10-15 Adolfas Dargys , Arturas Acus

We generalize the Hamiltonian picture of General Relativity coupled to classical matter, known as geometrodynamics, to the case where such matter is described by a Quantum Field Theory in Curved Spacetime, but gravity is still described by…

General Relativity and Quantum Cosmology · Physics 2024-03-20 J. L. Alonso , C. Bouthelier-Madre , J. Clemente-Gallardo , D. Martínez-Crespo

We investigate some properties of geometric operators in canonical quantum gravity in the connection approach \`a la Ashtekar, which are associated with volume, area and length of spatial regions. We motivate the construction of analogous…

General Relativity and Quantum Cosmology · Physics 2009-10-28 R. Loll

We show that the Floquet Hamiltonian of a quantum particle driven by a general time-periodic imaginary potential is exactly equivalent, at stroboscopic times, to the Hamiltonian of a free particle constrained to a curved Riemannian manifold…

Quantum Physics · Physics 2025-10-15 Samuel Alperin

This paper proposes a method of unifying quantum mechanics and gravity based on quantum computation. In this theory, fundamental processes are described in terms of pairwise interactions between quantum degrees of freedom. The geometry of…

Quantum Physics · Physics 2018-04-11 Seth Lloyd

Unitarity is a cornerstone of quantum theory, ensuring the conservation of probability and information. Although non-Hermitian Hamiltonians are typically associated with open or dissipative systems, pseudo-Hermitian quantum mechanics shows…

High Energy Physics - Theory · Physics 2025-11-03 Ruifeng Leng , Cheng-Yang Lee , Siyi Zhou

Quantum circuit complexity has played a central role in recent advances in holography and many-body physics. Within quantum field theory, it has typically been studied in a Lorentzian (real-time) framework. In a departure from standard…

High Energy Physics - Theory · Physics 2022-10-12 Josiah Couch , Yale Fan , Sanjit Shashi

More than 15 years ago, a new approach to quantum mechanics was suggested, in which Hermiticity of the Hamiltonian was to be replaced by invariance under a discrete symmetry, the product of parity and time-reversal symmetry, $\mathcal{PT}$.…

High Energy Physics - Theory · Physics 2015-06-04 Kimball A. Milton , E. K. Abalo , Prachi Parashar , Nima Pourtolami , J. Wagner

We extend the method for constructing symmetry operators of higher order for two-dimensional quantum Hamiltonians by Kalnins, Kress and Miller (2010). This expansion method expresses the integral in a finite power series in terms of lower…

Mathematical Physics · Physics 2025-05-26 Ian Marquette , Anthony Parr

The qualitatively new concept of dynamic complexity in quantum mechanics is based on a new paradigm appearing within a nonperturbational analysis of the Schroedinger equation for a generic Hamiltonian system. The unreduced analysis…

Quantum Physics · Physics 2007-05-23 Andrei P. Kirilyuk

In a recent paper it was shown that if a Hamiltonian H has an unbroken PT symmetry, then it also possesses a hidden symmetry represented by the linear operator C. The operator C commutes with both H and PT. The inner product with respect to…

Quantum Physics · Physics 2009-11-07 Carl M. Bender , Peter N. Meisinger , Qinghai Wang

A number of many-body problems can be formulated using Hamiltonians that are quadratic in the creation and annihilation operators. Here, we show how such quadratic Hamiltonians can be efficiently estimated indirectly, employing very few…

Quantum Physics · Physics 2011-01-17 Daniel Burgarth , Koji Maruyama , Franco Nori

We study a generalized version of the Hamiltonian constraint operator in nonperturbative loop quantum gravity. The generalization is based on admitting arbitrary irreducible SU(2) representations in the regularization of the operator, in…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Marcus Gaul , Carlo Rovelli

Quantum mechanics in its presently known formulation requires an external classical time for its description. A classical spacetime manifold and a classical spacetime metric are produced by classical matter fields. In the absence of such…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. P. Singh

Experimental implementations of quantum computer architectures are now being investigated in many different physical settings. The full set of requirements that must be met to make quantum computing a reality in the laboratory [1] is…

Quantum Physics · Physics 2009-11-06 D. P. DiVincenzo , D. Bacon , J. Kempe , G. Burkard , K. B. Whaley

For a (classically) integrable quantum mechanical system with two degrees of freedom, the functional dependence $\hat{H}=H_Q(\hat{J}_1,\hat{J}_2)$ of the Hamiltonian operator on the action operators is analyzed and compared with the…

Chaotic Dynamics · Physics 2009-10-31 Vyacheslav V. Stepanov , Gerhard Muller

We present the problem of approximating the time-evolution operator $e^{-i\hat{H}t}$ to error $\epsilon$, where the Hamiltonian $\hat{H}=(\langle G|\otimes\hat{\mathcal{I}})\hat{U}(|G\rangle\otimes\hat{\mathcal{I}})$ is the projection of a…

Quantum Physics · Physics 2019-07-17 Guang Hao Low , Isaac L. Chuang

We have constructed a set of non-Hermitian operators that satisfy the commutation relations of the SO(3)-Lie algebra. It is shown that this operators generate rotations in the configuration space and not in the momentum space but in a…

Mathematical Physics · Physics 2010-01-12 Juan M. Romero , R. Bernal-Jaquez , O. Gonzalez-Gaxiola

It has been argued that it is incompatible to maintain unitary time-evolution for time-dependent non-Hermitian Hamiltonians when the metric operator is explicitly time-dependent. We demonstrate here that the time-dependent Dyson equation…

Quantum Physics · Physics 2016-04-27 Andreas Fring , Miled H. Y. Moussa

Quasi-Hermitian quantum systems, including $\mathcal{PT}$-symmetric ones, can be mapped to equivalent Hermitian systems via a similarity transformation that redefines the inner product with a positive-definite metric operator. Although an…

Quantum Physics · Physics 2026-05-12 Ming-Zhang Wang , Xu-Yang Hou , Hao Guo