Papers by Roberto Baginski Batista Santos
Lecture Notes in Physics, 2001
ABSTRACT We show how the indistinguishable nature of the interaction of a collection of cold atom... more ABSTRACT We show how the indistinguishable nature of the interaction of a collection of cold atoms with the electromagnetic field in an optical cavity leads to entanglement and a very fast radiative decay dynamics. This acceleration of spontaneous emission has important consequences in the process known as radiative escape, one of the most important sources of trap loss due to cold collisions. In this process, a pair of atoms excited at some internuclear separation R C picks up kinetic energy on the long range excited state potential. The spontaneous emission time is a crucial parameter in this dynamics for it will determine whether or not the pair gains enough kinetic energy to escape from the trap. Considering realistic experimental parameters we can predict a very large suppression of radiative escape trap loss in a sample of cold rubidium atoms.
2011 12th European Conference on Radiation and Its Effects on Components and Systems, 2011
ABSTRACT IV-characteristics from ELT Overlapping Circular-Gate Transistors (O-CGT's) and ... more ABSTRACT IV-characteristics from ELT Overlapping Circular-Gate Transistors (O-CGT's) and rectangular-gate transistors are cross-checked after X-ray exposure. No degradation on O-CGT subthreshold behavior observed for doses up to 2.3 Grad. Devices were prototyped on standard 0.35 µm CMOS process.
Coherence and Quantum Optics VIII, 2003
We show how the modified electromagnetic vacuum of a resonant optical cavity can be used to manip... more We show how the modified electromagnetic vacuum of a resonant optical cavity can be used to manipulate the collisional dynamics between cold atoms by a modification of spontaneous emission times. Multiparticle entanglement and a higher spectral density of modes enhance spontaneous emission and alter the dynamics of cold collisions. A specific situation is considered and we show this effect can be observed as a large suppression in trap-loss rates.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2012
Modern Physics Letters B, 1997
We discuss a simple model where the electron is approximately described by a rapidly spinning dis... more We discuss a simple model where the electron is approximately described by a rapidly spinning disk of radius λ=ℏ/mc, such that the linear speed at its border is c. We assume that the particle's mass is uniformly distributed over the surface of the disk and its electric charge is strongly peaked around the border. It follows that the spin of the particle must be ℏ/2 and its magnetic moment should have a g factor equal to 2. We show that the electromagnetic self-energy of the particle is given by an expression which is similar to the result obtained in quantum electrodynamics.
Proceedings of 10th Latin American Symposium on Nuclear Physics and Applications — PoS(X LASNPA), 2014
In this work, P-and N-MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) were submitted ... more In this work, P-and N-MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) were submitted to X-ray and ion beams. CD 4007, a commercial off-the-shelf integrated circuit composed of six transistors, three P-type and three N-type, in a single package, was used. The integrated circuits were exposed to 60 MeV 35 Cl ion beams using the São Paulo 8UD Pelletron Accelerator and 10 keV X-ray radiation, using a Shimadzu XRD-7000 X-ray diffractometer. The total dose effects due to ionizing radiation in MOSFET were analyzed. The results indicate V th depends on the absorbed dose and dose rate. The deviation of V th is higher for P-MOS, while the change in slope is higher for N-MOS. TID (Total Ionizing Dose) caused by heavy ion does not seem to affect mobility. After heat treatment, the device establishes a different equilibrium state compared to that achieved at room temperature. The heat treatment worsens the P-type characteristics and improves the N-type.
Coupled oscillators are among the simplest composite quantum systems in which the interplay of en... more Coupled oscillators are among the simplest composite quantum systems in which the interplay of entanglement and interaction may be explored. We examine the effects of coupling on the quantum fluctuations of the coordinates and momenta of the oscillators in a single-excitation entangled Bell-like state. We discover that coupling acts as a mechanism for noise transfer between one pair of coordinate and momentum and another. Through this noise transfer mechanism, the uncertainty product is lowered, on average, relatively to its non-coupled level for one pair of coordinate and momentum and it is enhanced for the other pair. This novel mechanism for noise transfer may be explored in precision measurements in entanglement-assisted sensing and metrology.
2017 18th IEEE Latin American Test Symposium (LATS), 2017
Electronic systems functionality degrades when these systems are operating in harsh environments ... more Electronic systems functionality degrades when these systems are operating in harsh environments such as those where they are exposed to ionizing radiation. Understanding and measuring these effects is extremely important in order to design systems that can operate reliably. This work discusses experimental data of heavy ion and x-ray radiation effects on a Commercial-Off-The-Shelf (COTS) low-cost microprocessor. The heavy ions test results suggest that, in this technology, the SRAM is more sensitive to SEE than flash memory. Ions with a LET higher than 5 MeV/mg/cm 2 may disrupt the device's proper operation.
Revista de Ensino de Engenharia, 2018
niture or to purchase additional equipment and exactly the same content was covered in the active... more niture or to purchase additional equipment and exactly the same content was covered in the active learning and in the traditional lecture course sections. Qualitatively, observation of the students' attitudes during the term and analysis of the comments they made in the evaluation of the subject and of their teachers allowed us to conclude that the students perceive that engagement in their own learning affects positively their conceptual understanding and their problema solving skills, besides indicating that they prefer to be taught through an active methodology.
Journal of Physics: Conference Series, 2019
An updated overview of recent results on Heavy-Ion induced reactions of interest for neutrinoless... more An updated overview of recent results on Heavy-Ion induced reactions of interest for neutrinoless double beta decay is reported in the framework of the NUMEN project. The NUMEN idea is to study heavy-ion induced Double Charge Exchange (DCE) reactions with the aim to get information on the nuclear matrix elements for neutrinoless double beta (0νββ) decay. Moreover, to infer the neutrino average masses from the possible measurement of the half- life of 0νββ decay, the knowledge of the nuclear matrix elements is a crucial aspect.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2012
EPL (Europhysics Letters), 2012
Inspired by a recently observed asymmetry in the transmission of circularly polarized light throu... more Inspired by a recently observed asymmetry in the transmission of circularly polarized light through a metamaterial, we present a non-hermitian PT-symmetric quantum model to describe the interaction of the light fields in two resonant cavities coupled via a 2D-chiral mirror. We compute the time evolution of the light fields in this model, find two sets of operators compatible with the hamiltonian in a delocalized representation, discover the energies of the system and show that the transmission probability predicted by the model is indeed asymmetric.
Modern Physics Letters B, 2014
We present a simple non-Hermitian model to describe the phenomenon of asymmetric tunneling betwee... more We present a simple non-Hermitian model to describe the phenomenon of asymmetric tunneling between two energy-degenerate sites coupled by a non-reciprocal interaction without dissipation. The system was described using a biorthogonal family of energy eigenvectors, the dynamics of the system was determined by the Schrödinger equation, and unitarity was effectively restored by proper normalization of the state vectors. The results show that the tunneling rates are indeed asymmetrical in this model, leading to an equilibrium that displays unequal occupation of the degenerate systems even in the absence of external interactions.
International Journal of Modern Physics B, 1999
We discuss, in the context of classical electrodynamics with a Lorentz invariant cutoff at short ... more We discuss, in the context of classical electrodynamics with a Lorentz invariant cutoff at short distances, the self-force acting on a point charged particle. It follows that the electromagnetic mass of the point charge occurs in the equation of motion in a form consistent with special relativity. We find that the exact equation of motion does not exhibit runaway solutions or non-causal behavior, when the cutoff is larger than half of the classical radius of the electron.
We present two models for the electron in classical electrodynamics, which include some effects f... more We present two models for the electron in classical electrodynamics, which include some effects from quantum electrodynamics. In the first model, the electron is treated as an extended particle owing to the high-frequency oscillations (Zitterbewegung) of its electrical charge. We show that this model predicts correctly the magnitude of the electron spin and it gives the electron the same gyromagnetic factor as predicted by Dirac equation without radiative corrections. In this model, the electron self-energy has a logarithmic divergence due to the extended distribution of its electric charge. In the second model, virtual pair creation around the electron is taken into account by a generalization of the lagrangian for the electromagnetic field that preserves the symmetries of classical electrodynamics. This generalization changes the interaction of the electron with the electromagnetic field at small distances and allows us to evaluate the self-force of a point particle in a consistent way. We show that the solutions of the derived equation of motion do not exhibit self-acceleration nor pre-acceleration, being consistent with causality.
We analyze wave propagation in the vacuum of Podolsky regularized electrodynamics. Two kinds of w... more We analyze wave propagation in the vacuum of Podolsky regularized electrodynamics. Two kinds of waves were found in the theory: the traditional non-dispersive waves of Maxwell electrodynamics, and a dispersive wave reminiscent of wave propagation in a collisionless plasma. Charged particle concentration was determined, and found to be huge in this vacuum. We interpret the results in terms of vacuum polarization effects induced in an otherwise classical theory.
Modern Physics Letters A, 2011
We analyze wave propagation in the vacuum of Podolsky regularized electrodynamics. Two kinds of w... more We analyze wave propagation in the vacuum of Podolsky regularized electrodynamics. Two kinds of waves were found in the theory: the traditional non-dispersive waves of Maxwell electrodynamics, and a dispersive wave reminiscent of wave propagation in a collisionless plasma. Charged particle concentration was determined, and found to be huge in this vacuum. We interpret the results in terms of vacuum polarization effects induced in an otherwise classical theory.
Physics Letters A, 1998
The interaction of a microscopic magnetic dipole and the inductor of a RLC circuit without batter... more The interaction of a microscopic magnetic dipole and the inductor of a RLC circuit without batteries, is described using the approach of stochastic electrodynamics. The purpose of this study is to clarify the effects of the current fluctuations on the paramagnetic behaviour of a sample of magnetic material which is close to a thin solenoid. A suppression is predicted in the average magnetization, even in the case in which the circuit temperature is arbitrarily close to the absolute zero.
Physics Letters A, 1999
The interaction between a very thin macroscopic solenoid, and a single magnetic particle precessi... more The interaction between a very thin macroscopic solenoid, and a single magnetic particle precessing in a external magnetic field Bo, is described by taking into account the thermal and the zero-point fluctuations of stochastic electrodynamics. The inductor belongs to a RLC circuit without batteries and the random motion of the magnetic dipole generates in the solenoid a fluctuating current &ip( 1), and a fluctuating voltage &ip( t). with spectral distribution quite different from the Nyquist noise. We show that the mean square value (Z~ip) presents an enormous variation when the frequency of precession approaches the frequency of the circuit, but it is still much smaller than the Nyquist current in the circuit. However, we also show that (I,&) can reach measurable values if the inductor is interacting with a macroscopic sample of magnetic particles (atoms or nuclei) which are close enough to its coils.
Uploads
Papers by Roberto Baginski Batista Santos