With accretion discs one can probe the strong gravity regime in the near vicinity of Black Holes. In this talk the general formalism for accretion disks in stationary axially symmetric Black Hole space-times is developed. In the case of matter models based on ideal fluids analytic solutions fort the density and pressure can be found. The formalism can be extended to charged fluids. In...
In this presentation we review some experimental and theoretical results obtained in our group related to laser ablation and laser patterning. The need of developing original solutions for obtaining nanostructured materials is raised. Furthermore we report on a new method that combines the Laser Ablation and the Sol-Gel techniques in order to obtain nanostructured glasses. Au nanoparticles are...
Time-reversal symmetry and its violation is one of the most powerful concepts in physics. It has applications in many physics subfields ranging from condensed matter, optics and atomic physics to mathematical physics and quantum field theories. In this talk, we will focus on two specific implementations of time-reversal symmetry (and its violation) in the field of electrodynamics with...
Photodetectors based on nanostructured semiconductor materials have been successfully used in advanced communications, flame detection, air purification, ozone sensing and leak detection, among others, in the past few decades. We present fabrication and characterization of photodetectors based on nanomaterials using their nanocolloids prepared by Liquid-phase Pulsed Laser Ablation technique...
The advent of gravitational wave astronomy has created opportunities to probe strong-field gravity as black holes merge. Numerical relativity provides the means to confront the measurements with theoretical prediction from general relativity, allowing us to interpret the sources of gravitational waves and to test whether general relativity is the theory governing these events. This talk will...
The diffraction of atomic and molecular beams is typically described by non-trivial solutions of the stationary Schroedinger equation. This has been done for structureless particles in the absence of external fields. In this contribution, the techniques that incorporate both internal composition and a gravitational field are presented. A derivation of the corresponding propagator is provided...
Nanoparticles (NPs) of Au and Ag were obtained by laser synthesis and processing of colloids, including laser ablation, fragmentation and melting in liquids. Some parameters as the laser pulse energy (from few mJ to100 mJ) and repetition rate of the laser pulses (RRLP, in the range from 1– 10 Hz), as well as the lens to target distance (LTD) were varied, which produced changes in the...
Materials that have properties of two-photon absorption (2PA), such as cyanine dyes, have wide applications in emerging areas such as coherent laser control, optical limiting, photofarmacology or 3-dimensional imaging of biological tissue [1,2]. In this study, the efficiency of 2PA of cyanines was explored by the two-photon induced fluorescence (TPIF) technique with a femtosecond laser [3]. An...
This review describes the discovery of gravitational waves. We recount the journey of predicting and finding those waves, since its beginning in the early twentieth century, their prediction by Einstein in 1916, theoretical and experimental blunders, efforts towards their detection, and finally the subsequent successful discovery.
We show that it is possible emulate the pz orbitals of aromatic molecules using mechanical vibrations. This is done from the theoretical, numerical and experimental points of view. When connecting resonators through locally periodic structures, the resonances can be trapped thanks to the bandgaps of the locally periodic connectors [1,2]. This trapping yields a similar phenomenology to what...
Pulsed laser ablation in liquid (PLAL) is an interesting green technique to synthesize nanoparticles of metals, semiconductors, polymers and ceramics. We have synthesized nanoparticles of metals, semiconductors and ceramics using PLAL. Also explored the effects ablation wavelength, fluence and post irradiation effects on the morphology and properties of nanomaterials fabricated. From these...
The energy that carries an electromagnetic wave can be transferred to a chemical species via absorption. Once the molecule is in an excited state, it relaxes through various photophysical and photochemical channels [1]. Molecular dynamics is important because it involves the various deactivation channels through which the excitation energy dissipates. This study investigates the dynamics of...
We describe a particular excursion into the study of the localization phenomenon, kept within a family of simple model systems for the scattering of a propagating wave. The models are fully solvable and suitable for revealing an analogous nonlinear dynamical problem. A recursion relation for the system-size dependence of the scattering matrix relates to a bifurcation diagram where single point...
Detecting the electromagnetic (EM) counterpart of gravitational waves (GW) sources gives us with a wealth of information to understand the properties of the GW precursors. The fusion of neutron stars (NS) binaries has been identified as sources of GW. NS-NS fusions are also strong sources of EM radiation,they are called kilonovae. The light produced by kilonovae is mostly red, due to the...
CICESE was the first institution in México to build and operate (three decades ago) an ultrashort pulse laser system in México. In year 2003 we created the laboratory of ultrashort pulse lasers and processing of materials. Since then we have consolidated a research group that focuses on the following topics: fs laser-induced metallic oxides; fs laser-writing of photonics structures in...
I will speak about experiments with flat microwave resonators with and without induced time-reversal invariance violation. The scattering matrix formalism for such systems is equivalent to that developed for the random matrix theory description of compound nuclear reactions. Accordingly, the extraordinary advantage of such experiments is that they render possible the experimental verification...
Hypothetical ultralight bosonic particles have been suggested as (fuzzy) dark matter candidates. Such particles will spontaneously form macroscopic bosonic halos around spinning astrophysical black holes (BH), via an energy extraction process called superradiance, transferring part of the mass and angular momentum of the BH into the halo. I consider the phenomenology of this process, and of...
In the field of catalysis research and catalyst development especially tailored catalyst design is only possible when structure-activity correlations are mechanistically understood [1]. To that end, catalyst materials with gradually tuned properties are required. A promising tool to deliver nanomaterials with increasingly altered properties (e.g. band gap or photo-luminescence) and...
We will present a brief overview of CIO´s experimental work on ablation and micro-machining using an ultrafast amplified system (50 fs, 1 kHz). Specifically, we will cover surface nano- and micro-machining of stainless steel to achieve superhydrophobicity; also, we will present results on nanoparticle ablation from solid targets immersed in liquid.
One may think of classical stochastic processes as arising from the evolution of an open quantum system in the limit of strong decoherence. From this perspective, one would start with a quantum system, assume a coupling to the environment and eventually reach the classical stochastic process in the limit of strong decoherence. Here, we to proceed in the opposite direction: Given a...
If a black hole is seen against a backdrop of light sources, it shows a black disc known as the ``shadow'' of the black hole. In the first part of the talk I recall how the boundary curve of the shadow can be analytically calculated for an isolated (Schwarzschild or Kerr) black hole. Then I discuss how the cosmic expansion, in the simplest case just driven by a
cosmological constant, would...
The laser ablation of solids in liquid medium has been actively used in the last two decades for the synthesis and processing of nanoparticles. An important effect of the plasma formation as a result of the laser-solid interaction is that some of the plasma surrounding liquid is vaporized producing a cavitation bubble. This bubble expands to its maximum size and then collapses, this process...
In this talk we present the research studies at Escuela Superior de Física y Matemáticas-IPN and Facultad de Química-UAQ with the use of the Pulse Laser Deposition (PLD) technique. The research work is oriented to the following topics, namely: a) The thin film processing and characterization by PLD and applications as white light emitters of HfO2; b) Thin film processing and characterization...
We present a review of some important results obtained in the field of propagation and localization of waves in one-dimensional models with correlated disorder. In particular, we discuss how specific correlations of the random potential can give rise to peculiar transport properties in random media. We analyze some of the techniques used to deal with correlated disorder, including the...
Very soon the gravitational wave ground based detectors will hit the 50 binary Black Hole mergers detection milestone. This means that in less than five years, our knowledge about the existence of BHs have increased fivefold compared to what we have learned in the previous 40 years before the first gravitational wave detection.
What have we learned from gravitational wave astronomy about...
Cholesterol monolayers were deposited by the Langmuir-Blodgett (LB) technique on silicon wafers, glass slides, nano structured silicon wafers and nanostructured glass slides. These latter substrates are known as nanostructured substrates (SN) since they have deposited a silver film by the pulsed laser ablation technique (ALP). The films were characterized by the Raman spectroscopy technique to...
Two-dimensional (2D) van der Waals (vdW) heterostructures are a new realm of materials with potential applications and fascinating physical properties. Besides graphene (G), transition metal dichalcogenides (TMDCs) have been considered as promising building blocks in 2D vdW heterostructures with improved and new properties. The vertical stacking of at least two atomic monolayers bonded by vdW...
Lead-free piezoelectric materials were developed during the second half of the past century, among them, the potassium sodium niobate (K0.5Na0.5)NbO3 (KNN), KNN-based ferroelectrics and based ferroelectrics in Titanates of Barium (BaTiO3), are considered a promising lead-free materials alternative to Pb(Zr,Ti)O3 (PZT,) particularly the KNN by its high Curie temperature (Tc). Using PLD (pulsed...
Supermassive black holes with their extreme gravitational fields are at the forefront of research in extragalactic astrophysics. This talk outlines some of the major discoveries in black hole astrophysics, from early ideas to the most recent breakthroughs.
The laser induce periodic surface structures (LIPSS) have attracted considerable attention due to its potential to change, improve or provide new features to material surfaces. LIPSS appear as a quasi periodic pattern of parallel lines on the surface after being irradiated with linearly polarized laser radiation. These structures can be generated in a single-step process and their...
Pulsed laser deposition of thin films has proven to be a highly versatile technique for the growth of a number of different materials for almost any application. However, for the deposition of alloys, compounds or composite films, there are some drawbacks regarding targets preparation due to the deposited film is composed of two of more elements, making necessary the fabrication of targets...
Modeling black hole as punctures in space-time is common in binary black hole simulations. As the punctures approach each other, a common apparent horizon forms, signaling the coalescence of the black holes and the formation of the final black hole. In the first part of the talk, I will present results about the fate of the merging punctures inside the final black hole. While most studies of...
We will discuss the dynamics of quantum states in an energy transport model (photosynthesis) with a generator defined in terms of operators performing transitions between two mutually orthogonal subspaces, similar to birth and death transitions in classical stochastic processes or creation and annihilation operators in the quantum setting. It turns out that any stationary state has a portion...
In this work we report the synthesis of Graphite nanoparticles by laser ablation of a Graphite target immersed in distilled water. The laser used is a Nd: YAG emitting at 1064 nm with a pulsed length of 10 ns. The effect of an ultrasonic excitation and the laser energy density on the size and shape of the nanoparticles is investigated. The nanoparticles size and shape are determined from...
Material welding techniques have been a key aspect in the last industrial era. In fact, still there are some welding challenging applications that involve ceramic characteristics i. e. joining pieces of components in which biocompatibility or extremely high temperatures are in play. High temperature resistance of ceramics makes its welding a complex and difficult process.
The present work...
The theory of General relativity was postulated by Albert Einstein at the end of 1915. One of its main predictions was the existence of gravitational waves, that is perturbations of the geometry of space-time that travel at the speed of light, and are produced by violent astrophysical phenomena, sus as supernova explosions or the collisions of compact objects. However, gravitational waves are...
The supersymmetric formulation of quantum mechanics is a subject of intense activity in contemporary physics. It is addressed to analyze the spectral properties of exactly solvable potentials as well as to construct new integrable quantum models. In this talk we revisit the progress of such formulation since the introduction of the factorization method by Dirac to the construction of...
It has been demonstrated that carbon-based compounds, namely Expanded Graphite (EG), have become excellent fillers to reinforce polymers as Poly (ethylene terephthalate) (PET) to improve their mechanical resistance or electrical conductivity. Additionally, nanostructuring of polymers allows the modification of surface properties. A study about the generation of Laser Induced Periodic Surface...
