72 citations · 386 across the 30 of their papers we have counts for
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Phase space geometry of general quantum energy transitions
Alfredo M. Ozorio de Almeida
The mixed density operator for coarsegrained eigenlevels of a static Hamiltonian is represented in phase space by the spectral Wigner function, which has its peak on the correspond…
Semiclassical approximation of the Wigner function for the canonical ensemble
Marcos Gil de Oliveira, Alfredo Miguel Ozorio de Almeida
The Weyl-Wigner representation of quantum mechanics allows one to map the density operator in a function in phase space - the Wigner function - which acts like a probability distri…
Exact Markovian evolution of quantum systems with several degrees of freedom : Phase space representations
Aldo R. Fernandes Neto, Alfredo M. Ozorio de Almeida, Olivier Brodier
The exact solution of the Lindblad equation with a quadratic Hamiltonian and linear coupling operators was derived within the chord representation, that is, for the Fourier transfo…
The quantum canonical ensemble in phase space
Alfredo M. Ozorio de Almeida, Gert-Ludwig Ingold, Olivier Brodier
The density operator for a quantum system in thermal equilibrium with its environment depends on Planck's constant, as well as the temperature. At high temperatures, the Weyl repre…
Distinguishing quantum features in classical propagation
Kelvin Titimbo, Gabriel M. Lando, Alfredo M. Ozorio de Almeida
The strictly classical propagation of an initial Wigner function, referred to as TWA or LSC-IVR, is considered to provide approximate averages, despite not being a true Wigner func…
Representation of superoperators in double phase space
Marcos Saraceno, Alfredo M. Ozorio de Almeida
Operators in quantum mechanics - either observables, density or evolution operators, unitary or not - can be represented by c-numbers in operator bases. The position and momentum b…
Negativity witness for the quantum ergodic conjecture
Alfredo M. Ozorio de Almeida
For an ergodic system, the time average of a classical observable coincides with that obtained via the Liouville probability density, a delta-function on the energy shell. Reinterp…
Semiclassical theory for small displacements
Eduardo Zambrano, Alfredo M. Ozorio de Almeida
Characteristic functions contain complete information about all the moments of a classical distribution and the same holds for the Fourier transform of the Wigner function: a quant…
Complex WKB Evolution of Markovian Open Systems
O. Brodier, A. M. Ozorio de Almeida
We derive a semiclassical approximation for the evolution generated by the Lindblad equation as a generalization of complex WKB theory. Linear coupling to the environment is assume…
Uniform approximation for the overlap caustic of a quantum state with its translations
Eduardo Zambrano, Alfredo M Ozorio de Almeida
The semiclassical Wigner function for a Bohr-quantized energy eigenstate is known to have a caustic along the corresponding classical closed phase space curve in the case of a sing…
Semiclassical Evolution of Dissipative Markovian Systems
A. M. Ozorio de Almeida, P. de M. Rios, O. Brodier
A semiclassical approximation for an evolving density operator, driven by a "closed" hamiltonian operator and "open" markovian Lindblad operators, is obtained. The theory is based…
On resumming periodic orbits in the spectra of integrable systems
Alfredo M. Ozorio de Almeida, Caio H. Lewenkopf, Steven Tomsovic
Spectral determinants have proven to be valuable tools for resumming the periodic orbits in the Gutzwiller trace formula of chaotic systems. We investigate these tools in the conte…
The Weyl representation on the torus
A. M. F. Rivas, A. M. Ozorio de Almeida
We construct reflection and translation operators on the Hilbert space corresponding to the torus by projecting them from the plane. These operators are shown to have the same grou…