9,950 research outputs found
Demystifying “Pornography”: Tailoring Special Release Conditions Concerning Pornography and Sexually Oriented Expression
[Excerpt] “This article examines the design of special release conditions and the problems that arise when such conditions do not comport with constitutional standards. Part I provides a general overview of the First Amendment issues that often arise with respect to special release conditions. Part II discusses the current state of the law and classifies the types of bans defendants have encountered in supervised release conditions. Part III explains the factors that are frequently considered in assessing the validity of special release conditions, and Part IV suggests a new approach for evaluating the constitutionality of special release conditions. The article concludes by endorsing constitutionally permissible tailoring for release conditions and by encouraging courts to interpret these conditions with careful attention to the individual defendant’s situation.
Entanglement sudden death and sudden birth in two uncoupled spins
We investigate the entanglement evolution of two qubits interacting with a
common environment trough an Heisenberg XX mechanism. We reveal the possibility
of realizing the phenomenon of entanglement sudden death as well as the
entanglement sudden birth acting on the environment. Such analysis is of
maximal interest at the light of the large applications that spin systems have
in quantum information theory
Sensitivity of Measurement-Based Purification Processes to Inner Interactions
The sensitivity of a repeated measurement-based purification scheme to
additional undesired couplings is analyzed, focusing on the very simple and
archetypical system consisting of two two-level systems interacting with a
repeatedly measured one. Several regimes are considered and in the strong
coupling (i.e., when the coupling constant of the undesired interaction is very
large) the occurrence of a quantum Zeno effect is proven to dramatically
jeopardize the efficiency of the purification process.Comment: 12 pages, 6 figure
A criterion for entanglement in two two-level systems
We prove a necessary and sufficient condition for the occurrence of
entanglement in two two-level systems, simple enough to be of experimental
interest. Our results are illustrated in the context of a spin star system
analyzing the exact entanglement evolution of the central couple of spins.Comment: 4 pages, Submitted to Physical Review Letter
Interaction of bimodal fields with few-level atoms in cavities and traps
The spectacular experimental results of the last few years in cavity quantum
electrodynamics and trapped ions research has led to very high level laboratory
performances. Such a stimulating situation essentially stems from two decisive
advancements. The first is the invention of reliable protocols for the
manipulation of single atoms. The second is the ability to produce desired
bosonic environments on demand. These progresses have led to the possibility of
controlling the form of the coupling between individual atoms and an arbitrary
number of bosonic modes. As a consequence, fundamental matter-radiation
interaction models like, for instance, the JC model and most of its numerous
nonlinear multiphoton generalizations, have been realized or simulated in
laboratory and their dynamical features have been tested more or less in
detail. This topical paper reviews the state of the art of the theoretical
investigations and of the experimental observations concerning the dynamical
features of the coupling between single few-level atoms and two bosonic modes.
In the course of the paper we show that such a configuration provides an
excellent platform for investigating various quantum intermode correlation
effects tested or testable in the cavity quantum electrodynamics and trapped
ion experimental realms. In particular we discuss a mode-mode correlation
effect appearing in the dynamics of a two-level atom quadratically coupled to
two bosonic modes. This effect, named parity effect, consists in a high
sensitivity to the evenness or oddness of the total number of bosonic
excitations.Comment: Topical Review. To appear on J. Mod. Op
Preparation of macroscopically distinguishable superpositions of circular or linear oscillatory states of a bidimensionally trapped ion
Synchronizing Quantum Harmonic Oscillators through Two-Level Systems
Two oscillators coupled to a two-level system which in turn is coupled to an
infinite number of oscillators (reservoir) are considered, bringing to light
the occurrence of synchronization. A detailed analysis clarifies the physical
mechanism that forces the system to oscillate at a single frequency with a
predictable and tunable phase difference. Finally, the scheme is generalized to
the case of oscillators and two-level systems.Comment: 9 pages, 3 figure
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