Search results for "Quantum physic"

On the study of the vibrational energy levels of Arsine molecule

2008

Abstract We compare two formalisms applied to the vibrational modes of the molecule of AsH 3 of C 3 v molecular symmetry group. Indeed, the close stretching modes of this molecule may be considered as those of a three-dimensional oscillator whereas the bending modes may be considered either as a one-dimensional oscillator of symmetry A 1 and a two-dimensional oscillator of symmetry E or as an approximate three-dimensional oscillator. So, we have applied the U ( p  + 1) formalism to the both stretching and bending modes and introduced coupling terms acting on an appropriate coupled vibrational basis through a local mode formalism. We have then compared the result of our fitting with those ob…

Fault-Reconstruction-Based Cascaded Sliding Mode Observers for Descriptor Linear Systems

2012

Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/623426 This paper develops a cascaded sliding mode observer method to reconstruct actuator faults for a class of descriptor linear systems. Based on a new canonical form, a novel design method is presented to discuss the existence conditions of the sliding mode observer. Furthermore, the proposed method is extended to general descriptor linear systems with actuator faults. Finally, the effectiveness of the proposed technique is illustrated by a simulation example.

Observer-Based Stabilization of Stochastic Systems with Limited Communication

2012

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from Hindawi: http://dx.doi.org/10.1155/2012/781542 Open Access This paper studies the problem of observer-based stabilization of stochastic nonlinear systems with limited communication. A communication channel exists between the output of the plant and the input of the dynamic controller, which is considered network-induced delays, data packet dropouts, and measurement quantization. A new stability criterion is derived for the stochastic nonlinear system by using the Lyapunov functional approach. Based on this, the design procedure of observer-based controller is presented,which ensures asy…

Robust Observer Design for Takagi-Sugeno Fuzzy Systems with Mixed Neutral and Discrete Delays and Unknown Inputs

2012

Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/635709 A robust observer design is proposed for Takagi-Sugeno fuzzy neutral models with unknown inputs. The model consists of a mixed neutral and discrete delay, and the disturbances are imposed on both state and output signals. Delay-dependent sufficient conditions for the design of an unknown input T-S observer with time delays are given in terms of linear matrix inequalities. Some relaxations are introduced by using intermediate variables. A numerical example is given to illustrate the effectiveness of the given results.

Spatial correlations of vacuum fluctuations and the Casimir-Polder potential

2003

We calculate the Casimir-Polder intermolecular potential using an effective Hamiltonian recently introduced. We show that the potential can be expressed in terms of the dynamical polarizabilities of the two atoms and the equal-time spatial correlation of the electric field in the vacuum state. This gives support to an interesting physical model recently proposed in the literature, where the potential is obtained from the classical interaction between the instantaneous atomic dipoles induced and correlated by the vacuum fluctuations. Also, the results obtained suggest a more general validity of this intuitive model, for example when external boundaries or thermal fields are present.

Josephson Traveling Wave Parametric Amplifiers as Non-Classical Light Source for Microwave Quantum Illumination

2021

Abstract Detection of low-reflectivity objects can be enriched via the so-called quantum illumination procedure. In order that this quantum procedure outperforms classical detection protocols, entangled states of microwave radiation are initially required. In this paper, we discuss the role of Josephson Traveling Wave Parametric Amplifiers (JTWPAs), based on circuit-QED components, as suitable sources of a two-mode squeezed vacuum state, a special signal-idler entangled state. The obtained wide bandwidth makes the JTWPA an ideal candidate for generating quantum radiation in quantum metrology and information processing applications.

Vibrational Spectra of Polyatomic Molecules through an Algebraic Approach

1987

The study of molecular oscillators may be performed with algebraic methods based upon dynamical chains and their realization in terms of boson operators. From the dynamical algebra U(p+1) for p equivalent oscillators, associated with stretching modes, the local, pseudo-normal and normal limits are obtained through appropriate subgroup chains and various realizations of the U(p+1) generators. Similar technics can be applied to bending modes. Application to XY4 molecules will be presented.

Rovibrational interactions in the local-mode limit. The (n000) stretching overtone bands of spherical tops.

1993

A study of Wigner functions for discrete-time quantum walks

2013

We perform a systematic study of the discrete time Quantum Walk on one dimension using Wigner functions, which are generalized to include the chirality (or coin) degree of freedom. In particular, we analyze the evolution of the negative volume in phase space, as a function of time, for different initial states. This negativity can be used to quantify the degree of departure of the system from a classical state. We also relate this quantity to the entanglement between the coin and walker subspaces.

Oб определении внутримолекулярной потенциальной функции многоатомной молекулы H2S

2008

In modern molecular physics, there are two basic methods of determining the intramolecular potential function of polyatomic molecules. The first method is ab initio calculations and the second is the so-called semi-empirical method in which the Hamiltonian parameters are varied by direct construction of the Hamiltonian matrix. In the present work, the second approach is discussed on the example of the XY2 three-atomic molecule of the C2v symmetry. On the one hand, it is extremely simple for implementation, and on the other hand, it considerably extends the capability of application of the traditional semi-empirical methods. The approach suggested involves two aspects that make it advantageo…