Search results for "Boson"
showing 10 items of 1360 documents
A concise review on pseudo-bosons, pseudo-fermions and their relatives
2017
We review some basic definitions and few facts recently established for $\D$-pseudo bosons and for pseudo-fermions. We also discuss an extended version of these latter, based on biorthogonal bases, which lives in a finite dimensional Hilbert space. Some examples are described in details.
Dynamics of a subconstituent picture of weak interactions
1985
We use sum rules in order to discuss the dynamics of the simplest subconstituent model of weak interactions with elementary spin 1/2 fermions and scalar bosons. Vacuum condensates of the scalars play an essential role and lead to features quite different from QCD. With a certain vacuum structure vector dominance of the composite W-mesons is a good approximation, and we also see a clear signal for massless fermions in the two-point function of composite fermions. Thus such a model is in good agreement with standard phenomenology. Composite Higgs particles are also investigated. The effective interaction is evidently of the gauge type.
Quantum Phases in a Resonantly Interacting Boson-Fermion Mixture
2005
We consider a resonantly-interacting Bose-Fermi mixture of $^{40}$K and $^{87}$Rb atoms in an optical lattice. We show that by using a red-detuned optical lattice the mixture can be accurately described by a generalized Hubbard model for $^{40}$K and $^{87}$Rb atoms, and $^{40}$K-$^{87}$Rb molecules. The microscopic parameters of this model are fully determined by the details of the optical lattice and the interspecies Feshbach resonance in the absence of the lattice. We predict a quantum phase transition to occur in this system already at low atomic filling fraction, and present the phase diagram as a function of the temperature and the applied magnetic field.
Search for a multi-Higgs-boson cascade inW+W−bb¯events with the ATLAS detector inppcollisions ats=8 TeV
2014
A search is presented for new particles in an extension to the Standard Model that includes a heavy Higgs boson (H-0), an intermediate charged Higgs-boson pair (H-+/-), and a light Higgs boson (h(0)). The analysis searches for events involving the production of a single heavy neutral Higgs boson which decays to the charged Higgs boson and a W boson, where the charged Higgs boson subsequently decays into a W boson and the lightest neutral Higgs boson decaying to a bottom-antibottom-quark pair. Such a cascade results in a W-boson pair and a bottom-antibottom-quark pair in the final state. Events with exactly one lepton, missing transverse momentum, and at least four jets are selected from a d…
Three-mode two-boson Jaynes–Cummings model in trapped ions
2006
In this paper, we analyse a two-boson three-mode Jaynes–Cummings model which can be implemented in the context of trapped ions. The symmetries of the Hamiltonian are brought to light and analysed in detail in order to solve the eigenvalue problem. The calculation of the time evolution operator shows the possibility of realizing interesting applications, such as the generation of nonclassical states.
(Regular) pseudo-bosons versus bosons
2012
We discuss in which sense the so-called {\em regular pseudo-bosons}, recently introduced by Trifonov and analyzed in some details by the author, are related to ordinary bosons. We repeat the same analysis also for {\em pseudo-bosons}, and we analyze the role played by certain intertwining operators, which may be bounded or not.
Critical Behavior for Correlated Strongly Coupled Boson Systems in 1 + 1 Dimensions
1994
The natural integrable correlated strongly coupled boson system in 1 + 1 dimensions is the $q$-boson hopping model; we calculate its critical exponent $\ensuremath{\theta}$ and determine its correlation functions. For small couplings the $q$-boson model has natural connections with the Bose gas and the $\mathrm{XY}$ models of very large spin for which $\ensuremath{\theta}'\mathrm{s}$ and correlators are reported. For large couplings the hopping model is a new phase of interacting bosons substantially different from the impenetrable Bose gas.
Tracking the time-evolution of the electron distribution function in Copper by femtosecond broadband optical spectroscopy
2019
Multitemperature models are nowadays often used to quantify the ultrafast electron-phonon (boson) relaxations and coupling strengths in advanced quantum solids. To test their applicability and limitations, we perform systematic studies of carrier relaxation dynamics in copper, a prototype system for which the two-temperature model (TTM) was initially considered. Using broadband time-resolved optical spectroscopy, we study the time evolution of the electron distribution function, $f(E)$, over a large range of excitation densities. Following intraband optical excitation, $f(E)$ is found to be athermal over several 100 fs, with a substantial part of the absorbed energy already being transferre…
Dynamical formation and stability of fermion-boson stars
2020
Gravitationally bound structures composed by fermions and scalar particles known as fermion-boson stars are regular and static configurations obtained by solving the coupled Einstein-Klein-Gordon-Euler (EKGE) system. In this work, we discuss one possible scenario through which these fermion-boson stars may form by solving numerically the EKGE system under the simplifying assumption of spherical symmetry. Our initial configurations assume an already existing neutron star surrounded by an accreting cloud of a massive and complex scalar field. The results of our simulations show that once part of the initial scalar field is expelled via gravitational cooling the system gradually oscillates aro…
Lightest Higgs boson production at photon colliders in the two Higgs doublet model type III
2005
The branching ratios of the lightest $CP$-even Higgs boson ${h}^{0}$ are calculated in the framework of the general two higgs doublet model. Different scenarios are presented taking into account constraints on the flavor changing neutral currents factors obtained in previous works. Plausible scenarios where appear flavor changing processes at tree level like $b\overline{s}$ and $t\overline{c}$ are analyzed for relevant parameters. The loop-induced Higgs couplings to photon pairs can be tested with a photon collider. The number of events of ${h}^{0}$ as a resonance in photon colliders are calculated taking into account its corresponding background signal at TESLA, CLIC, and NLC.