A5083224685- Advancements in Semiconductor Devices and Circuit Design
- Quantum and electron transport phenomena
- Semiconductor materials and devices
- Pulsars and Gravitational Waves Research
- Semiconductor Quantum Structures and Devices
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Surface and Thin Film Phenomena
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- Quantum chaos and dynamical systems
- Theoretical and Computational Physics
- Quantum optics and atomic interactions
- Physics of Superconductivity and Magnetism
- Dark Matter and Cosmic Phenomena
- High-pressure geophysics and materials
- Semiconductor materials and interfaces
- Mechanical and Optical Resonators
- Advanced Frequency and Time Standards
- Radio Astronomy Observations and Technology
- Radio Frequency Integrated Circuit Design
- Experimental and Theoretical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Adaptive optics and wavefront sensing
- Integrated Circuits and Semiconductor Failure Analysis
Institut Català de Ciències del Clima
2025
Institut de Ciències del Cosmos
2025
Universitat de Barcelona
2003-2024
University of Portsmouth
2022
Commonwealth Scientific and Industrial Research Organisation
2000
Université de Montpellier
2000
Universidad Carlos III de Madrid
1995-1998
National Academy of Sciences of Ukraine
1992-1998
Universidad de Salamanca
1997-1998
In this Letter, we present the design and performance of frequency-dependent squeezed vacuum source that will be used for broadband quantum noise reduction Advanced Virgo Plus gravitational-wave detector in upcoming observation run. The field is generated by a phase rotation frequency-independent state through 285 m long, high-finesse, near-detuned optical resonator. With about 8.5 dB squeezing, up to 5.6 suppression has been measured at high frequency while close filter cavity resonance...
Spatio-temporal chaos is predicted to occur in n-doped semiconductor superlattices with sequential resonant tunneling as their main charge transport mechanism. Under dc voltage bias, undamped time-dependent oscillations of the current (due motion and recycling electric field domain walls) have been observed recent experiments. Chaos result forcing this natural oscillation by means an appropriate external microwave signal.
Shot-noise suppression is investigated in nondegenerate diffusive conductors by means of an ensemble Monte Carlo simulator. The universal 1/3 value obtained when transport occurs under elastic collision regime provided the following conditions are satisfied: (i) applied voltage much larger than thermal value; (ii) length device longer both mean free path and Debye length. By fully suppressing carrier-number fluctuations, long range Coulomb interaction essential to obtain low-frequency limit.
Self-sustained time-dependent current oscillations under dc voltage bias have been observed in recent experiments on n-doped semiconductor superlattices with sequential resonant tunneling. The are caused by the motion and recycling of domain wall separating low- high-electric- field regions superlattice, as analysis a discrete drift model shows experimental evidence supports. Numerical simulation that different nonlinear dynamical regimes appear when an external microwave signal is...
When gravitational waves propagate near massive objects, their paths curve resulting in lensing, which is expected to be a promising new instrument astrophysics. If the time delay between different comparable with wave period, lensing may induce beating patterns waveform, and it very close caustics that these effects are likely observable. Near caustic, however, short-wave asymptotics associated geometrical optics approximation breaks down. In order describe properly crossover from regimes,...
Abstract While completing the commissioning phase to prepare Virgo interferometer for next joint Observation Run (O4), collaboration is also finalizing design of upgrades detector be employed in following (O5). The major upgrade will concern decreasing thermal noise limit, which imply using very large test masses and increased laser beam size. But this not only implemented break between O4 O5 observation runs increase strain sensitivity. paper cover challenges linked implications on...
We present a microscopic analysis of shot-noise suppression due to long-range Coulomb interaction in semiconductor devices under ballistic transport conditions. An ensemble Monte Carlo simulator self-consistently coupled with Poisson solver is used for the calculations. A wide range injection-rate densities leading different degrees investigated. sharp tendency noise at increasing injection found scale dimensionless Debye length related importance space-charge effects structure.
We investigate the injection of degenerate Fermi-Dirac electrons into a multimode ballistic conductor under space-charge-limited regime. The nonequilibrium current fluctuations were found to be suppressed by both Coulomb and Fermi correlations. show that shot-noise-suppression factor is limited below value ${2k}_{B}T/{\ensuremath{\varepsilon}}_{F},$ where T temperature ${\ensuremath{\varepsilon}}_{F}$ energy injected electrons. noise suppression may attain much lower values...
Massive objects located between Earth and a compact binary merger can act as gravitational lenses magnifying signals improving the sensitivity of wave detectors to distant events. Depending on parameters system, point-mass lens detector source either lead smooth frequency-dependent amplification signal, or magnification combined with appearance second image that interferes first creating regular, predictable pattern. We map increase in signal noise ratio for upcoming LIGO-Virgo-KAGRA (LVK)...
Within a Monte Carlo simulation, we investigate the statistical properties of an electron flow injected with Poissonian distribution and transmitted under ballistic regime in presence long-range Coulomb interaction. Electrons are shown to exhibit motional squeezing which tends space them more regularly rather than strictly at random, evidence sub-Poissonian statistics substantially reduced Fano factor ${F}_{n}\ensuremath{\ll}1$. The temporal (anti)correlation among carriers is demonstrated...
We present a numerical simulation of shot-noise suppression due to long-range Coulomb interaction in nondegenerate ballistic transport. Calculations make use an ensemble Monte Carlo simulator self-consistently coupled with one-dimensional Poisson solver, and are applied semiconductor structure formed lightly doped active region surrounded by two contacts acting as reservoirs. The doping the injecting voltage taken variable parameters. At increasing voltages transition from thermal conditions...
A self-consistent theory of shot noise in ballistic two-terminal conductors under the action long-range Coulomb correlations is presented. Analytical formulas for electron distribution function and its fluctuation along conductor, which account correlations, have been derived. Based upon these formulas, current-noise reduction factor has obtained biases ranging from thermal to shot-noise limits as dependent on two parameters: ratio between length sample Debye screening...
The reduction of quantum scattering leads to the suppression shot noise. In this Letter, we analyze crossover from transport regime with universal noise classical where vanishes. By making use stochastic path integral approach, find statistics and transmission properties a chaotic cavity as function system parameter controlling crossover. We identify three different scenarios
We study the interference and diffraction of light when it propagates through a metamaterial medium mimicking spacetime cosmic string, -- topological defect with curvature singularity. The phenomenon may look like gravitational analogue Aharonov-Bohm effect, since in region where Riemann tensor vanishes being nonetheless affected by non-zero confined to string core. carry out full-wave numerical simulation give analytical interpretation results use asymptotic theory diffraction, which turns...
The multifractal dimension of chaotic attractors has been studied in a weakly coupled superlattice driven by an incommensurate sinusoidal voltage as function the driving amplitude. derived for observed bifurcation sequence shows different characteristics chaotic, quasiperiodic, and frequency-locked attractors. In regime, strange are observed. Even quasiperiodic with certain degree strangeness may exist. From dimensions, deterministic nature oscillations is clearly identified.
We investigate the current injection into a ballistic conductor under space-charge limited regime, when distribution function of injected carriers is an arbitrary energy ${F}_{c}(\ensuremath{\varepsilon}).$ The analysis coupled kinetic and Poisson equations shows that fluctuations may be essentially suppressed by Coulomb correlations, suppression level determined shape This in contrast to time-averaged quantities: mean spatial profiles are shown insensitive...
We have analyzed the shot noise of electron emission under strong applied electric fields within Landauer-B\"uttiker scheme. In contrast to previous studies vacuum-tube emitters, we show that in new generation scaled down nanometer dimensions, much smaller than Schottky is observable. Carbon nanotube field emitters are among possible candidates observe effect shot-noise suppression caused by quantum partitioning.
We present a theoretical investigation of shot-noise suppression due to long-range Coulomb interaction in nondegenerate diffusive conductors. Calculations make use an ensemble Monte Carlo simulator self-consistently coupled with one-dimensional Poisson solver. analyze the noise lightly doped active region surrounded by two contacts acting as thermal reservoirs. By taking doping injecting and applied voltage variable parameters, influence elastic inelastic scattering is investigated. The...
We review recent theoretical investigations of shot-noise suppression in nondegenerate semiconductor structures surrounded by two contacts acting as thermal reservoirs. Calculations make use an ensemble Monte Carlo simulator self-consistently coupled with a one-dimensional Poisson solver. By taking the doping injecting and applied voltage variable parameters, influence elastic inelastic scattering well tunneling between heterostructures active region is investigated. In case homogeneous...
Electron scattering on a thin layer where the potential depends self-consistently wave function has been studied. When amplitude of incident exceeds certain threshold, soliton-shaped brightening (darkening) appears causing diffraction wave. Thus spontaneously formed transverse pattern can be viewed as self-induced nonlinear quantum screen. Attractive or repulsive nonlinearities result in different phase shifts screen, which give rise to quite patterns. Among others, nonlinearity cause...