436 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Consejo Nacional de Investigaciones Científicas y TécnicasAR144 papers
- Universidad Nacional de La PlataAR72 papers
- Universidad de ColimaMX41 papers
- Centro Científico Tecnológico - La PlataAR40 papers
- Institute for Complex SystemsIT23 papers
- Sapienza University of RomeIT22 papers
- University of TrentoIT18 papers
- Centre National de la Recherche ScientifiqueFR13 papers
- Instituto de Fisica de Liquidos y Sistemas BiologicosAR13 papers
- University of MichiganUS12 papers
- Cornell UniversityUS11 papers
- University of CambridgeGB11 papers
73 papers · 1 filter
Is the matrix completion of reduced density matrices unique?
Gustavo E. Massaccesi, Ofelia B. Oña, Luis Lain +4
Reduced density matrices are central to describing observables in many-body quantum systems. In electronic structure theory, the two-particle reduced density matrix (2-RDM) suffice…
Determining the ensemble N-representability of Reduced Density Matrices
Ofelia B. Oña, Gustavo E. Massaccesi, Pablo Capuzzi +5
The N-representability problem for reduced density matrices remains a fundamental challenge in electronic structure theory. Following our previous work that employs a unitary-evolu…
Determining the N-representability of a reduced density matrix via unitary evolution and stochastic sampling
Gustavo. E. Massaccesi, Ofelia. B. Oña, Pablo Capuzzi +6
The N-representability problem consists in determining whether, for a given p-body matrix, there exists at least one N-body density matrix from which the p-body matrix can be obtai…
Statistics of the Random Matrix Spectral Form Factor
Alex Altland, Francisco Divi, Tobias Micklitz +2
The spectral form factor of random matrix theory plays a key role in the description of disordered and chaotic quantum systems. While its moments are known to be approximately Gaus…
Oddities in the Entanglement Scaling of the Quantum Six-Vertex Model
Sunny Pradhan, Jesús Cobos, Enrique Rico +1
We investigate the entanglement properties of the Quantum Six-Vertex Model on a cylinder, focusing on the Shannon-Renyi entropy in the limit of Renyi order . This entro…
On the Raleigh-Ritz variational method. Non-orthogonal basis set
Francisco M. Fernández
We overview the main equations of the Rayleigh-Ritz variational method and discuss their connection with the problem of simultaneous diagonalization of two Hermitian matrices.
Maximal Clauser-Horne-Shimony-Holt violation for qubit-qudit states
Alexander Bernal, J. Alberto Casas, Jesus M. Moreno
We evaluate the maximal Clauser-Horne-Shimony-Holt (CHSH) violation for a generic (typically mixed) qubit-qudit state, obtaining easily computable expressions in arbitrary qudit di…
On the eigenvalues of the harmonic oscillator with a Gaussian perturbation
Paolo Amore, Francisco M. Fernández, Javier Garcia
We test the analytical expressions for the first two eigenvalues of the harmonic oscillator with a Gaussian perturbation proposed recently. Our numerical eigenvalues show that thos…
Photonic implementation of the quantum Morra game
Andres Ulibarrena, Alejandro Sopena, Russell Brooks +4
In this paper, we study a faithful translation of a two-player quantum Morra game, which builds on previous work by including the classical game as a special case. We propose a nat…
On the effective secular equation
Francisco M. Fernández
We show that the effective secular equation proposed several years ago is suitable for estimating the location of the exceptional points of eigenvalue equations. As an illustrative…
Comment on: "On the characteristic polynomial of an effective Hamiltonian"
Francisco M. Fernández
We show that a method proposed recently, based on the characteristic polynomial of an effective Hamiltonian, had been developed several years earlier by other authors in a clearer…
Algebraic analysis of non-Hermitian quadratic Hamiltonians
Francisco M. Fernández
We study a general one-mode non-Hermitian quadratic Hamiltonian that does not exhibit -symmetry. By means of an algebraic method we determine the conditions for the e…
Extremely broken generalized symmetry
Francisco M. Fernández
We discuss some simple Hückel-like matrix representations of non-Hermitian operators with antiunitary symmetries that include generalized (parity transformation foll…
An ubiquitous three-term recurrence relation
Paolo Amore, Francisco M. Fernández
We solve an eigenvalue equation that appears in several papers about a wide range of physical problems. The Frobenius method leads to a three-term recurrence relation for the coeff…
A most misunderstood conditionally-solvable quantum-mechanical model
Francisco M. Fernández
In this paper we show that several authors have derived wrong physical conclusions from a gross misunderstanding of the exact eigenvalues and eigenfunctions of a conditionally-solv…
On a class of non-Hermitian Hamiltonians with tridiagonal matrix representation
Francisco M. Fernández
We show that some non-Hermitian Hamiltonian operators with tridiagonal matrix representation may be quasi Hermitian or similar to Hermitian operators. In the class of Hamiltonian o…
Comment on: "Bound states and the potential parameter spectrum". J. Math. Phys. \textbf{67}, 062103 (2020)
Francisco M. Fernández
We analyze the application of the "tridiagonal representation approach" (TRA) to the Schrödinger equation for some simple, exactly-solvable, quantum-mechanical models. In the case…
Comment on: "Aharonov-Bohm effect for bound states from the interaction of the magnetic quadrupole moment of a neutral particle with axial fields". Phys. Rev. A 101, 032102 (2020)
Francisco M. Fernández
We analyze recently published results about the Aharonov-Bohm effect for bound states from the interaction of the magnetic quadrupole moment of a neutral particle with axial fields…
Comment on: "Solving many-body Schrödinger equations with kinetic energy partition method'', Ann. Phys. 388 (2018) 54-68 by Y-H. Chen and S. D. Chao
Francisco M. Fernández
We discuss a recent test of the performance of the kinetic energy partition method (KEP) through its application to two separable quantum-mechanical models. We argue that one of th…
Gross misinterpretation of a conditionally solvable eigenvalue equation
Paolo Amore, Francisco M. Fernández
We solve an eigenvalue equation that appears in several papers about a wide range of physical problems. The Frobenius method leads to a three-term recurrence relation for the coeff…
Comment on: "Some quantum aspects of a particle with electric quadrupole moment interacting with an electric field subject to confining potentials". Int. J. Mod. Phys. A 29 (2014) 1450117
Francisco M. Fernández
We analyze the results obtained from a model consisting of the interaction etween the electric quadrupole moment of a moving particle and an electric field. We argue that the syste…
Comment on "Bidimensional bound states for charged polar nanoparticles''
Paolo Amore, Francisco M. Fernández
In a recent paper Castellanos-Jaramillo and Castellanos-Moreno proposed a simple quantum-mechanical model for an electron in the vicinity of an ionized nanostructure with a permane…
On the Hellmann-Feynman theorem in statistical mechanics
Paolo Amore, Francisco M. Fernández
In this paper we develop the Hellmann-Feynman theorem in statistical mechanics without resorting to the eigenvalues and eigenvectors of the Hamiltonian operator. Present approach d…
Comment on: "The asymptotic iteration method revisited" [J. Math. Phys. 61, 033501 (2020)]
Francisco M. Fernández
In this comment we show that the eigenvalues of a quartic anharmonic oscillator obtained recently by means of the asymptotic iteration method may not be as accurate as the authors…