Search results for "Quantum physic"
showing 10 items of 1596 documents
Global-to-local incompatibility, monogamy of entanglement, and ground-state dimerization: Theory and observability of quantum frustration in systems …
2015
Frustration in quantum many body systems is quantified by the degree of incompatibility between the local and global orders associated, respectively, to the ground states of the local interaction terms and the global ground state of the total many-body Hamiltonian. This universal measure is bounded from below by the ground-state bipartite block entanglement. For many-body Hamiltonians that are sums of two-body interaction terms, a further inequality relates quantum frustration to the pairwise entanglement between the constituents of the local interaction terms. This additional bound is a consequence of the limits imposed by monogamy on entanglement shareability. We investigate the behavior …
Quantum walk on a cylinder
2016
We consider the 2D alternate quantum walk on a cylinder. We concentrate on the study of the motion along the open dimension, in the spirit of looking at the closed coordinate as a small or "hidden" extra dimension. If one starts from localized initial conditions on the lattice, the dynamics of the quantum walk that is obtained after tracing out the small dimension shows the contribution of several components, which can be understood from the study of the dispersion relations for this problem. In fact, these components originate from the contribution of the possible values of the quasi-momentum in the closed dimension. In the continuous space-time limit, the different components manifest as …
Analysis of high excited "hot" bands of the SO2 molecule
2011
The main goal of the present study is to analyse rotational structures of highly excited "hot" vibrational bands, v1+2v2-v2 and 2v2+v3-v2, v2+3v3-v2 and 2v1+v2+v3-v2, and v2+2v3-v2. All of these bands are located in the region of considerably stronger bands, v1 + v2 and v2 + v3, 3v3 and 2v1+v3, and 2v3, respectively . On that reason, as the first step of analysis, we made assignments of transitions belonging to these strong bands. As the result of analysis, we were able to assign three times more transitions to the bands v1 + v2 , v2 + v3, and 3v3 (3360 transitions with Jmax. = 78 and Kmax.a = 27 to the band v1 + v2, and 2380 transitions with Jmax. = 69 and Kmax.a = 24 to the band v2 + v3, …
Vibrational modes of the stibine molecule
2005
International audience; In this paper, we use the algebraic approach to describe the vibrational modes of stibine molecule (of C3v molecular symmetry group) up to 21 quanta. As the stibine molecule exhibits stretch-bend resonances, we build an algebraic pyramidal coupling operator between stretching modes and bending modes adapted to this molecule. The standard deviation associated to the fit of the vibrational levels is 1.75 cm-1.
Quantum search of spatial regions
2003
Can Grover's algorithm speed up search of a physical region - for example a 2-D grid of size sqrt(n) by sqrt(n)? The problem is that sqrt(n) time seems to be needed for each query, just to move amplitude across the grid. Here we show that this problem can be surmounted, refuting a claim to the contrary by Benioff. In particular, we show how to search a d-dimensional hypercube in time O(sqrt n) for d at least 3, or O((sqrt n)(log n)^(3/2)) for d=2. More generally, we introduce a model of quantum query complexity on graphs, motivated by fundamental physical limits on information storage, particularly the holographic principle from black hole thermodynamics. Our results in this model include a…
High Resolution Study of the v1 + 2v2 −v2 and 2v2 + v3 − v2 ”Hot” Bands and Ro-Vibrational Re-Analysis of the v1 + v2/v2 + v3/3v3 Poliad of the SO2 M…
2010
The main goal of the present study was to analyse rotational stuctures of two excited vibrational states, (120) and (021). Because both the band, v1+2v2 and 2v2+v3 one are extremally weak, a special efforts were faired to record very weak hot bands, v1+2v2−v2 and 2v2+v3−v2.Both of those bands are located in the region of considerably more stronger combinational bands, v1 + v2 and v2 + v3. On that reason, as the first step of analysis, we made assignments of transitions belonging to these v1 + v2 and v2 + v3 bands. As the result of analysis, we were able to assign three times more transitions to the bands v1 + v2 and v2 + v3 than it was known in the before literature. After "cleaning" the ex…
Lindblad equation approach for the full counting statistics of work and heat in driven quantum systems
2013
We formulate the general approach based on the Lindblad equation to calculate the full counting statistics of work and heat produced by driven quantum systems weakly coupled with a Markovian thermal bath. The approach can be applied to a wide class of dissipative quantum systems driven by an arbitrary force protocol. We show the validity of general fluctuation relations and consider several generic examples. The possibilities of using calorimetric measurements to test the presence of coherence and entanglement in the open quantum systems are discussed. QC 20141010
Hybrid nonlinear observer for Inertial Navigation
2016
This paper considers the problem of designing an observer for navigation and localization of inertial systems. Since the measurement systems used in this field have a low update rate with respect to the control algorithm, the design of a suitable observer with sampled measurements is required. Here a hybrid non-linear observer is proposed, combining two different observers with different characteristics. A theoretical treatment is given in order to prove the convergence of the observer and it will be contextualized in the framework of the hybrid systems, providing an elegant setting for the proposed solution. Finally experimental results show the feasibility of the proposed observer and the…
Quasi-Lie Brackets and the Breaking of Time-Translation Symmetry for Quantum Systems Embedded in Classical Baths
2018
Many open quantum systems encountered in both natural and synthetic situations are embedded in classical-like baths. Often, the bath degrees of freedom may be represented in terms of canonically conjugate coordinates, but in some cases they may require a non-canonical or non-Hamiltonian representation. Herein, we review an approach to the dynamics and statistical mechanics of quantum subsystems embedded in either non-canonical or non-Hamiltonian classical-like baths which is based on operator-valued quasi-probability functions. These functions typically evolve through the action of quasi-Lie brackets and their associated Quantum-Classical Liouville Equations, or through quasi-Lie brackets a…
Quantum entanglement of identical particles by standard information-theoretic notions
2016
Quantum entanglement of identical particles is essential in quantum information theory. Yet, its correct determination remains an open issue hindering the general understanding and exploitation of many-particle systems. Operator-based methods have been developed that attempt to overcome the issue. We introduce a state-based method which, as second quantization, does not label identical particles and presents conceptual and technical advances compared to the previous ones. It establishes the quantitative role played by arbitrary wave function overlaps, local measurements and particle nature (bosons or fermions) in assessing entanglement by notions commonly used in quantum information theory …