2,464 research outputs found
Epidermoid Cyst of Spleen
Splenic cysts are very rare lesions, most of them being parasitic systs. Nonparasitic cysts are uncommon. We report a case of young female who presented with mass and pain abdomen. Ultrasound examination revealed splenic syst. The diagnosis of epidermoid cyst was made based on characteristic lining on histopathological examinatio
From quantum stochastic differential equations to Gisin-Percival state diffusion
Starting from the quantum stochastic differential equations of Hudson and
Parthasarathy (Comm. Math. Phys. 93, 301 (1984)) and exploiting the
Wiener-Ito-Segal isomorphism between the Boson Fock reservoir space
and
the Hilbert space , where is the Wiener probability measure of
a complex -dimensional vector-valued standard Brownian motion
, we derive a non-linear stochastic Schrodinger
equation describing a classical diffusion of states of a quantum system, driven
by the Brownian motion . Changing this Brownian motion by an
appropriate Girsanov transformation, we arrive at the Gisin-Percival state
diffusion equation (J. Phys. A, 167, 315 (1992)). This approach also yields an
explicit solution of the Gisin-Percival equation, in terms of the
Hudson-Parthasarathy unitary process and a radomized Weyl displacement process.
Irreversible dynamics of system density operators described by the well-known
Gorini-Kossakowski-Sudarshan-Lindblad master equation is unraveled by
coarse-graining over the Gisin-Percival quantum state trajectories.Comment: 28 pages, one pdf figure. An error in the multiplying factor in Eq.
(102) corrected. To appear in Journal of Mathematical Physic
Separability bounds on multiqubit moments due to positivity under partial transpose
Positivity of the density operator reflects itself in terms of sequences of
inequalities on observable moments. Uncertainty relations for non-commuting
observables form a subset of these inequalities. In addition, criterion of
positivity under partial transposition (PPT) imposes distinct bounds on
moments, violations of which signal entanglement. We present bounds on some
novel sets of composite moments, consequent to positive partial transposition
of the density operator and report their violation by entangled multiqubit
states. In particular, we derive separability bounds on a multiqubit moment
matrix (based on PPT constraints on bipartite divisions of the density matrix)
and show that three qubit pure states with non-zero tangle violate these PPT
moment constraints. Further, we recover necessary and sufficient condition of
separability in a multiqubit Werner state through PPT bounds on moments.Comment: 16 pages, no figures, minor revisions, references added; To appear in
Phys. Rev.
A scheme for amplification and discrimination of photons
A scheme for exploring photon number amplification and discrimination is
presented based on the interaction of a large number of two-level atoms with a
single mode radiation field. The fact that the total number of photons and
atoms in the excited states is a constant under time evolution in Dicke model
is exploited to rearrange the atom-photon numbers. Three significant
predictions emerge from our study: Threshold time for initial exposure to
photons, time of perception (time of maximum detection probability), and
discrimination of first few photon states.Comment: 8 pages, 3 figures, RevteX, Minor revision, References adde
Kraus representation of quantum evolution and fidelity as manifestations of Markovian and non-Markovian avataras
It is shown that the fidelity of the dynamically evolved system with its
earlier time density matrix provides a signature of non-Markovian dynamics.
Also, the fidelity associated with the initial state and the dynamically
evolved state is shown to be larger in the non-Markovian evolution compared to
that in the corresponding Markovian case. Starting from the Kraus
representation of quantum evolution, the Markovian and non-Markovian features
are discerned in its short time structure. These two features are in
concordance with each other and they are illustrated with the help of four
models of interaction of the system with its environment.Comment: 7 pages, 5 eps figures; Discussion on recent characterizations of
non-Markovianity included in this versio
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