1,092 research outputs found
Unified scheme for correlations using linear relative entropy
A linearized variant of relative entropy is used to quantify in a unified
scheme the different kinds of correlations in a bipartite quantum system. As
illustration, we consider a two-qubit state with parity and exchange symmetries
for which we determine the total, classical and quantum correlations. We also
give the explicit expressions of its closest product state, closest classical
state and the corresponding closest product state. A closed additive relation,
involving the various correlations quantified by linear relative entropy, is
derived.Comment: 20 page
Quantum discord in photon added Glauber coherent states of -type
We investigate the influence of photon excitations on quantum correlations in
tripartite Glauber coherent states of Greenberger-Horne-Zeilinger type. The
pairwise correlations are measured by means of the entropy-based quantum
discord. We also analyze the monogamy property of quantum discord in this class
of tripartite states in terms of the strength of Glauber coherent states and
the photon excitation order.Comment: 20 page
A Geometric Parametrization of the Cabibbo-Kobayashi-Maskawa Matrix and the Jarlskog Invariant
In this paper we give a geometric parametrization to the
Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix and the Jarlskog invariant, which
is based on two flag manifolds . To treat a fourth generation
of quarks on CP violation we generalize the parametrization to one based on two
flag manifolds .Comment: Latex ; 14 pages ; 2 figures ; minor change
Reduced Dynamics from the Unitary Group to Some Flag Manifolds : Interacting Matrix Riccati Equations
In this paper we treat the time evolution of unitary elements in the N level
system and consider the reduced dynamics from the unitary group U(N) to flag
manifolds of the second type (in our terminology). Then we derive a set of
differential equations of matrix Riccati types interacting with one another and
present an important problem on a nonlinear superposition formula that the
Riccati equation satisfies.
Our result is a natural generalization of the paper {\bf Chaturvedi et al}
(arXiv : 0706.0964 [quant-ph]).Comment: Latex ; 13 pages ; no figur
Star-Like Micelles with Star-Like Interactions: A quantitative Evaluation of Structure Factor and Phase Diagram
PEP-PEO block copolymer micelles offer the possibility to investigate phase
behaviour and interactions of star polymers (ultra-soft colloids). A star-like
architecture is achieved by an extremely asymmetric block ratio (1:20).
Micellar functionality f can be smoothly varied by changing solvent composition
(interfacial tension). Structure factors obtained by SANS can be quantitatively
described in terms of an effective potential developed for star polymers. The
experimental phase diagram reproduces to a high level of accuracy the predicted
liquid/solid transition. Whereas for intermediate f a bcc phase is observed,
for high f the formation of a fcc phase is preempted by glass formation.Comment: 5 pages, 4 figures, PRL in pres
Guns and butter? Military expenditure and health spending on the eve of the Arab Spring
We examine the validity of the guns-versus-butter hypothesis in the pre-Arab Spring era. Using panel data from 1995 to 2011–the eve of the Arab uprisings–we find no evidence that increased security needs as measured by the number of domestic terrorist attacks are complemented by increased military spending or more importantly ‘crowd out’ government expenditure on key public goods such as health care. This suggests that both expenditure decisions were determined by other considerations at the government level
Muon spin rotation and neutron scattering study of the non-centrosymmetric tetragonal compound CeAuAl3
We have investigated the non-centrosymmetric tetragonal heavy-fermion
compound CeAuAl3 using muon spin rotation (muSR), neutron diffraction (ND) and
inelastic neutron scattering (INS) measurements. We have also revisited the
magnetic, transport and thermal properties. The magnetic susceptibility reveals
an antiferromagnetic transition at 1.1 K with a possibility of another magnetic
transition near 0.18 K. The heat capacity shows a sharp lambda-type anomaly at
1.1 K in zero-filed, which broadens and moves to higher temperature in applied
magnetic field. Our zero-field muSR and ND measurements confirm the existence
of a long-range magnetic ground state below 1.2 K. Further the ND study reveals
an incommensurate magnetic ordering with a magnetic propagation vector k = (0,
0, 0.52) and a spiral structure of Ce moments coupled ferromagnetically within
the ab-plane. Our INS study reveals the presence of two well-defined crystal
electric field (CEF) excitations at 5.1 meV and 24.6 meV in the paramagnetic
phase of CeAuAl3 which can be explained on the basis of the CEF theory.
Furthermore, low energy quasi-elastic excitations show a Gaussian line shape
below 30 K compared to a Lorentzian line shape above 30 K, indicating a
slowdown of spin fluctuation below 30 K. We have estimated a Kondo temperature
of TK=3.5 K from the quasi-elastic linewidth, which is in good agreement with
that estimated from the heat capacity. This study also indicates the absence of
any CEF-phonon coupling unlike that observed in isostructural CeCuAl3. The CEF
parameters, energy level scheme and their wave functions obtained from the
analysis of INS data explain satisfactorily the single crystal susceptibility
in the presence of two-ion anisotropic exchange interaction in CeAuAl3.Comment: 28 pages and 17 figure
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