arXiv subjects

Gustavo V. Lopez

Publications and source records attributed to Gustavo V. Lopez.

15 recordsLinked to original sources

arXiv2020

Study of galaxy morphology and merging time of two interacting galaxies under different initial rotation and orientation configurations

Using the GADGET-2 N-body code, we make a study of the galaxy morphology and merging time due to two interacting galaxies (for the same types and different sizes and masses, $1:1$ and $1:10$ ratio masses) merging due to gravity interaction. This is done for different initial relative orientation and rotation of these galaxies (modes of interaction) but with the same relative bulge separation and the same relative initial velocities. It was found that the resulting galaxy morphology resemble many of the observed galaxies in our Universe, and that, in general, a binary galaxy system with 1:10 mass ratio has larger merging time than a binary galaxy system with 1:1 mass ratio. This difference is due to the different evolution of the masses during the interaction in both cases. For the case with a 1:10 mass ratio, the global mass maximum is located at the end evolution, meaning that the second galaxy increases its mass constantly. For the case with mass ratio 1:1, the global maximum is located around $t=0.35$ Gy, causing a reduction of the merging time.

astro-ph.GA↗

arXiv2020

Charged particle in a flat box with static electromagnetic field and Landau's levels

We study the quantization of the motion of a charged particle without spin inside a flat box under a static electromagnetic field. Contrary to Landau's solution with constant magnetic field transverse to the box, we found a non separable variables solution for the wave function, and this fact remains when static electric field is added. However, the Landau's Levels appear in all cases.

physics.gen-ph↗

arXiv2017

On Maxwell-like equations for Gravitational Field

For explicitly time depending mass density, which satisfies a continuity equation, it is shown that Maxwell-like equations for gravitational field follow naturally without any need of General Relativity Theory approximation or related assumptions. As a consequences, it is shown that several features already known in Electrodynamics (Poynting vector, density of energy, tensor stress, radiation) are totally reproduced for gravitational field.

physics.gen-ph↗

arXiv2016

Nanbu-Goto action and qubit theory in any signature and higher dimensions

We perform an extension of the relation between the Nambu-Goto action and qubit theory. Of course, the Cayley hyperdeterminant is the key mathematical tool in such generalization. Using the Wick rotation we find that in four dimensions such a relation can be established no only in (2+2)-dimensions but also in any signature. We generalize our result to a curved space-time of (2$^{2n}$+2$^{2n}$)-dimensions and (2$^{2n+1}$+2$^{2n+1}$)-dimensions.

gr-qc↗

arXiv2016

Generalization of the Force Approach to Radiation Reaction

A generalization of the force approach to radiation reaction is given, taken into consideration an arbitrary motion of the charged particle . The expression obtained brings about the expression already given for the linear an the circular acceleration cases.

physics.class-ph↗

arXiv2015

About Factorization of Quantum States with Few Qubits

We study the factorization conditions of a wave function made up of states of two, three and four qubits and propose and analytical expression which can characterize entangled states in terms of the coefficients of the wave function and density matrix elements.

quant-ph↗

arXiv2015

Study of decoherence of entangled states made up of two basic states in a linear chain of three qubits

Using Lindblad approach to study decoherence of quantum systems, we study the decoherence and decay of entangled states, formed by two basic states of a chain of thee qubits. We look on these states for a possible regular dependence on their decay as a function of their energy separation between the basic states under different type of environments. We found not regular or significant dependence on this energy separation for the type of environment considered .

quant-ph↗

arXiv2014

About One-Dimensional Conservative Systems with Position Depending Mass

For a one-dimensional conservative systems with position depending mass, one deduces consistently a constant of motion, a Lagrangian, and a Hamiltonian for the non relativistic case. With these functions, one shows the trajectories on the spaces $(x,v)$ and ($x,p)$ for a linear position depending mass. For the relativistic case, the Lagrangian and Hamiltonian can not be given explicitly in general. However, we study the particular system with constant force and mass linear dependence on the position where the Lagrangian can be found explicitly, but the Hamiltonian remains implicit in the constant of motion.

physics.class-ph↗

arXiv2006

Chain of nuclear spins system quantum computer taking into account second neighbor Ising spins interaction and numerical simulation of Shor factorization of N=4

For a one-dimensional chain of four nuclear spins (1/2) and taking into account first and second neighbor interactions among the spin system, we make the numerical simulation of Shor prime factorization algorithm of the integer number N=4 to study the influence of the second neighbor interaction on the performance of this algorithm. It is shown that the optimum Rabi's frequency to control the non-resonant effects is dominated by the second neighbor interaction coupling parameter ($J'$), and that a good Shor quantum factorization is achieved for a ratio of second to first coupling constant of $J'/J\ge 0.04$.

quant-ph↗

arXiv2006

Simulation of an entangled state in a chain of three nuclear spins system

We study the formation of an entangled state in a one-dimensional chain of three nuclear spins system which interact weakly through the Ising type of interaction and taking into account first and second neighbor interactions. We can get this entangled state using two pulses ($π/2$ and $π$ pulses), and we study the efficiency of getting this entangled state as a function of the ratio of the second neighbor interaction coupling constant to the first neighbor interaction coupling constant ($J'/J$). We found that for $J'/J\ge 0.04$, the entangled state is well defined.

quant-ph↗

arXiv2006

Numerical simulation of Quantum Teleportation in a chain of three nuclear spins system taking into account second neighbor interaction

For a one-dimensional chain of three nuclear spins (one half), we make the numerical simulation of quantum teleportation of a given state from one end of the chain to the other end, taking into account first and second neighbor interactions among the spins. It is shown that a well defined teleportation protocol is achieved for a ratio of the first to second neighbor interaction coupling constant of $J'/J\ge 0.04$. We also show that the optimum Rabi's frequency to control the non-resonant effects is dominated by the second neighbor interaction coupling parameter ($J'$).

quant-ph↗

arXiv2006

Numerical simulation of a Controlled-Controlled-Not (CCN) quantum gate in a chain of three interacting nuclear spins system

We present the study of a quantum Controlled-Controlled-Not gate, implemented in a chain of three nuclear spins weakly Ising interacting between all of them, that is, taking into account first and second neighbor spin interactions. This implementation is done using a single resonant $π$-pulse on the initial state of the system (digital and superposition). The fidelity parameter is used to determine the behavior of the CCN quantum gate as a function of the ratio of the second neighbor interaction coupling constant to the first neighbor interaction coupling constant ($J'/J$). We found that for $J'/J\ge 0.02$ we can have a well defined CCN quantum gate.

quant-ph↗

arXiv2002

Qubitless Quantum Logic

We discuss the implementation of quantum logic in a system of strongly interacting particles. The implementation is qubitless since ``logical qubits'' don't correspond to any physical two-state subsystems. As an illustration, we present the results of simulations of the quantum controlled-NOT gate and Shor's algorithm for a chain of spin-1/2 particles with Heisenberg coupling. Our proposal extends the current theory of quantum information processing to include systems with permanent strong coupling between the two-state subsystems.

quant-ph↗

arXiv1998

Quantum Entangled States and Quasiclassical Dynamics in Macroscopic Spin Systems

When dealing with macroscopic objects one usually observes quasiclassical phenomena, which can be described in terms of quasiclassical (or classical) equations of motion. Recent development of the theory of quantum computation is based on implementation of the entangled states which do not have a classical analogy. Using a simple example of a paramagnetic spin system we show that the entangled states can be detected in standard macroscopic experiments as a sharp deviation from quasiclassical motion.

quant-ph↗

arXiv1998

Dynamics of a Quantum Control-Not Gate for an Ensemble of Four-Spin Molecules at Room Temperature

We investigate numerically a single-pulse implementation of a quantum Control-Not (CN) gate for an ensemble of Ising spin systems at room temperature. For an ensemble of four-spin ``molecules'' we simulate the time-evolution of the density matrix, for both digital and superpositional initial conditions. Our numerical calculations confirm the feasibility of implementation of quantum CN gate in this system at finite temperature, using electromagnetic $π$-pulse.

quant-ph↗