Comment on 'Generalized Heisenberg algebra coherent states for power-law potentials'

We argue that the statistical features of generalized coherent states for power-law potentials based on Heisenberg algebra, presented in a recent paper by Berrada et al (Phys. Lett. A, 375, 298 (2011)) are incorrect.Comment: 9 pages, 1 figur

Relaxation to a Phase-locked Equilibrium State in a One-dimensional Bosonic Josephson Junction

We present an experimental study on the non-equilibrium tunnel dynamics of two coupled one-dimensional Bose-Einstein quasi-condensates deep in the Josephson regime. Josephson oscillations are initiated by splitting a single one-dimensional condensate and imprinting a relative phase between the superfluids. Regardless of the initial state and experimental parameters, the dynamics of the relative phase and atom number imbalance shows a relaxation to a phase-locked steady state. The latter is characterized by a high phase coherence and reduced fluctuations with respect to the initial state. We propose an empirical model based on the analogy with the anharmonic oscillator to describe the effect of various experimental parameters. A microscopic theory compatible with our observations is still missing.Comment: 9 pages, 5 figure

Trading Volumes in Dynamically Efficient Markets

The classic Lucas asset pricing model with complete markets stresses aggregate risk and, hence, fails to investigate the impact of agents heterogeneity on the dynamics of the equilibrium quantities and measures of trading volume. In this paper, we investigate under what conditions non-informational heterogeneity, i.e. differences in preferences and endowments, leads to non trivial trading volume in equilibrium. Our main result comes in form of a non-informational no trade theorem which provides necessary and sufficient conditions for zero trading volume in a dynamically efficient, continuous time Lucas market model with multiple goods and securities.General Equilibrium, Trading Volume; heterogenous agents; multiple goods; incomplete markets; no-trade theorem.

Testing Component-Based Real Time Systems

International audienceThis paper focuses on studying efficient solutions for modeling and deriving compositional tests for component-based real-time systems. In this work, we propose a coherent framework that does not require the computation of the synchronous product (composition) of components, and therefore avoids a major bottleneck in this class of test. For this framework, we introduce an approach and associated algorithm. In our approach, the overall behavior of the system is obtained by restricting free runs of components to those involving interactions between them. This restriction is achieved through the use of a particular component called assembly controller. For the generation algorithm, compositional test cases are derived from the assembly controller model using symbolic analysis. This reduces the state space size (a practical size) and enables the generation of sequences which cover all critical interaction scenarios

Open quantum system description of singlet-triplet qubits in quantum dots

We develop a theoretical model to describe the dissipative dynamics of singlet-triplet (S-T_0) qubits in GaAs quantum dots. Using the concurrence experimentally obtained as a guide, we show that each logical qubit is coupled to its own environment because the decoherence effect can be described by independent dephasing channels. Given the correct description of the environment, we study the dynamics of concurrence as a function of the temperature, the constant coupling between the system and the environment, the preparation time, and the exchange coupling. Although the reduction of the environment coupling constant modifies the entanglement dynamics, we demonstrate that temperature emerges as a crucial variable and a variation of millikelvins significantly modifies the generation of entangled states. Furthermore, we show that the exchange coupling together with the preparation time strongly affects the entanglement dissipative dynamics.Comment: This version provides a description of the decoherence mechanism that is completely different from the published version. For a closer version see arXiv: 1701.0316