309 research outputs found
On the generation of multipartite entangled states in Josephson architectures
We propose and analyze a scheme for the generation of multipartite entangled
states in a system of inductively coupled Josephson flux qubits. The qubits
have fixed eigenfrequencies during the whole process in order to minimize
decoherence effects and their inductive coupling can be turned on and off at
will by tuning an external control flux. Within this framework, we will show
that a W state in a system of three or more qubits can be generated by
exploiting the sequential one by one coupling of the qubits with one of them
playing the role of an entanglement mediator.Comment: 10 pages, 3 figure
Interaction-free evolution in the presence of time-dependent Hamiltonians
The generalization of the concept of interaction-free evolutions (IFE) [A.
Napoli, {\it et al.}, Phys. Rev. A {\bf 89}, 062104 (2014)] to the case of
time-dependent Hamiltonians is discussed. It turns out that the time-dependent
case allows for much more rich structures of interaction-free states and
interaction-free subspaces. The general condition for the occurrence of IFE is
found and exploited to analyze specific situations. Several examples are
presented, each one associated to a class of Hamiltonians with specific
features.Comment: 6 pahes, no figure
Analytically solvable Hamiltonians for quantum two-level systems and their dynamics
A simple systematic way of obtaining analytically solvable Hamiltonians for
quantum two-level systems is presented. In this method, a time-dependent
Hamiltonian and the resulting unitary evolution operator are connected
through an arbitrary function of time, furnishing us with new analytically
solvable cases. The method is surprisingly simple, direct, and transparent and
is applicable to a wide class of two-level Hamiltonians with no involved
constraint on the input function. A few examples illustrate how the method
leads to simple solvable Hamiltonians and dynamics
Fluctuation theorems for non-Markovian quantum processes
Exploiting previous results on Markovian dynamics and fluctuation theorems,
we study the consequences of memory effects on single realizations of
nonequilibrium processes within an open system approach. The entropy production
along single trajectories for forward and backward processes is obtained with
the help of a recently proposed classical-like non-Markovian stochastic
unravelling, which is demonstrated to lead to a correction of the standard
entropic fluctuation theorem. This correction is interpreted as resulting from
the interplay between the information extracted from the system through
measurements and the flow of information from the environment to the open
system: Due to memory effects single realizations of a dynamical process are no
longer independent, and their correlations fundamentally affect the behavior of
entropy fluctuations.Comment: 7 pages, 1 figur
Efficient generation of -photon generalized binomial states in a cavity
Extending a previous result on the generation of two-photon generalized
binomial field states, here we propose an efficient scheme to generate with
high-fidelity, in a single-mode high-Q cavity, N-photon generalized binomial
states with a maximum number of photons N>2. Besides their interest for
classical-quantum border investigations, we discuss the applicative usage of
these states in realizing universal quantum computation, describing in
particular a scheme that performs a controlled-NOT gate by dispersive
interaction with a control atom. We finally analyze the feasibility of the
proposed schemes, showing that they appear to be within the current
experimental capabilities.Comment: 8 pages, 2 figure
Tomographic approach to the violation of Bell's inequalities for quantum states of two qutrits
The tomographic method is employed to investigate the presence of quantum
correlations in two classes of parameter-dependent states of two qutrits. The
violation of some Bell's inequalities in a wide domain of the parameter space
is shown. A comparison between the tomographic approach and a recent method
elaborated by Wu, Poulsen and Molmer shows the better adequacy of the former
method with respect to the latter one.Comment: 9 pages, 4 figure
Exact treatment of operator difference equations with nonconstant and noncommutative coefficients
We study a homogeneous linear second-order difference equation with nonconstant and noncommuting
operator coefficients in a vector space. We build its exact resolutive formula consisting of the explicit noniterative
expression of a generic term of the unknown sequence of vectors. Some nontrivial applications are reported in order
to show the usefulness and the broad applicability of the resul
Valproate in Conversion Disorder: A Case Report
Few data are in literature about the pharmacological treatment of conversion disorder and there are not any studies about the use of Valproate extended release (ER) in treating conversion disorder. In this article, we are reporting a case of an Italian woman with a diagnosis of conversion disorder treated effectively and quickly by Valproate ER
Quetiapine Sustained Release in Treatment of Delirium Induced by Cerebral Metastasis
While haloperidol represents the first-line treatment of delirium, some studies have shown that atypical antipsychotics could be used as an efficacious treatment in delirium management. This article reports a case of a delirious patient, treated effectively and quickly with Quetiapine sustained release with negligible side effects
- …