20,665 research outputs found
Finite Volume Cumulant Expansion in QCD-Colorless Plasma
Due to the finite size effects, the localisation of the phase transition in
finite systems and the determination of its order, become an extremely
difficult task, even in the simplest known cases. In order to identify and
locate the finite volume transition point of the QCD deconfinement
phase transition to a Colorless QGP, we have developed a new approach using the
finite size cumulant expansion of the order parameter and the -method.
The first six cumulants with the corresponding
under-normalized ratios(skewness , kurtosis ,pentosis
and hexosis ) and three unnormalized
combinations of them (, , ) are calculated and studied as functions of . A new approach,
unifying in a clear and consistent way the definitions of cumulant ratios, is
proposed. A numerical FSS analysis of the obtained results has allowed us to
locate accurately the finite volume transition point. The extracted transition
temperature value agrees with that expected from the
order parameter and the thermal susceptibility ,
according to the standard procedure of localization to within about . In
addition to this, a very good correlation factor is obtained proving the
validity of our cumulants method. The agreement of our results with those
obtained by means of other models is remarkable.Comment: 19 pages,14 figues, figures 4,5,6 figures are oversized, therefore,
can be obtained directly from [email protected],Accepted for publication in
EPJ
Pseudo-Unitary Operators and Pseudo-Unitary Quantum Dynamics
We consider pseudo-unitary quantum systems and discuss various properties of
pseudo-unitary operators. In particular we prove a characterization theorem for
block-diagonalizable pseudo-unitary operators with finite-dimensional diagonal
blocks. Furthermore, we show that every pseudo-unitary matrix is the
exponential of times a pseudo-Hermitian matrix, and determine the
structure of the Lie groups consisting of pseudo-unitary matrices. In
particular, we present a thorough treatment of pseudo-unitary
matrices and discuss an example of a quantum system with a
pseudo-unitary dynamical group. As other applications of our general results we
give a proof of the spectral theorem for symplectic transformations of
classical mechanics, demonstrate the coincidence of the symplectic group
with the real subgroup of a matrix group that is isomorphic to the
pseudo-unitary group U(n,n), and elaborate on an approach to second
quantization that makes use of the underlying pseudo-unitary dynamical groups.Comment: Revised and expanded version, includes an application to symplectic
transformations and groups, accepted for publication in J. Math. Phy
Ortho-Fluorination of azophenols increases the mesophase stability of photoresponsive hydrogen-bonded liquid crystals
Photoresponsive liquid crystals (LCs) whose alignment can be controlled with UV-Visible light are appealing for a range of photonic applications. From the perspective of exploring the interplay between the light response and the self-assembly of the molecular components, supramolecular liquid crystals are of particular interest. They allow elaborating the structure-property relationships that govern the optical performance of LC materials by subtle variation of the chemical structures of the building blocks. Herein we present a supramolecular system comprising azophenols and stilbazoles as hydrogen-bond donors and acceptors, respectively, and show that ortho-fluorination of the azophenol dramatically increases the thermal stability of the LC phases, an important characteristics in their further utilization in photonics. The systems exhibit fast photoinduced order-disorder transitions, and rapid recovery of the liquid-crystalline state once the light irradiation is ceased, due to the photochemical properties of azophenols
Pseudo-Hermitian Hamiltonians, indefinite inner product spaces and their symmetries
We extend the definition of generalized parity , charge-conjugation
and time-reversal operators to nondiagonalizable pseudo-Hermitian
Hamiltonians, and we use these generalized operators to describe the full set
of symmetries of a pseudo-Hermitian Hamiltonian according to a fourfold
classification. In particular we show that and are the generators of
the antiunitary symmetries; moreover, a necessary and sufficient condition is
provided for a pseudo-Hermitian Hamiltonian to admit a -reflecting
symmetry which generates the -pseudounitary and the -pseudoantiunitary
symmetries. Finally, a physical example is considered and some hints on the
-unitary evolution of a physical system are also given.Comment: 20 page
New features of scattering from a one-dimensional non-Hermitian (complex) potential
For complex one-dimensional potentials, we propose the asymmetry of both
reflectivity and transmitivity under time-reversal: and , unless the potentials are real or PT-symmetric. For complex
PT-symmetric scattering potentials, we propose that
and . So far, the spectral singularities (SS) of a one-dimensional
non-Hermitian scattering potential are witnessed/conjectured to be at most one.
We present a new non-Hermitian parametrization of Scarf II potential to reveal
its four new features. Firstly, it displays the just acclaimed (in)variances.
Secondly, it can support two spectral singularities at two pre-assigned real
energies () either in or in , when
. Thirdly, when it possesses one SS in
and the other in . Fourthly, when the potential becomes PT-symmetric
, we get , it possesses a unique SS at
in both and . Lastly, for completeness, when
and , there are no SS, instead we get two
negative energies and of the complex PT-symmetric Scarf
II belonging to the two well-known branches of discrete bound state eigenvalues
and no spectral singularity exists in this case. We find them as
and ; with
.
{PACS: 03.65.Nk,11.30.Er,42.25.Bs}Comment: 10 pages, one Table, one Figure, important changes, appeared as an
FTC (J. Phys. A: Math. Theor. 45(2012) 032004
Microbial dynamics during various activities in residential areas of Lahore, Pakistan
Bioaerosols are ubiquitous in the atmosphere with their levels affected by a variety of environmental factors as well as
type of activities being carried out at any specific time. The present study investigated how indoor activities influence
bioaerosol concentrations in five residential houses of Lahore. Agar coated petri plates were exposed face upwards for
twenty minutes in kitchens and living rooms during activity and non-activity periods. The temperature and relative
humidity levels were noted as well. The bioaerosol concentrations in kitchens during the activity time ranged between
1022 to 4481 cfu/m3 and in living rooms from 1179 to 3183 cfu/m3 . Lower values were observed during non-activity
periods. A paired-t test revealed a significant difference in bacterial loads during activity and non-activity times in both
micro-environments (p = 0.038 in kitchen and p = 0.021 in living room). The predominant species identified were
Micrococcus spp., Staphylococcus spp., and Bacillus spp. which are a common constituent of the indoor environment
and are known to be opportunistic pathogens as well
Analyzing Energy-efficiency and Route-selection of Multi-level Hierarchal Routing Protocols in WSNs
The advent and development in the field of Wireless Sensor Networks (WSNs) in
recent years has seen the growth of extremely small and low-cost sensors that
possess sensing, signal processing and wireless communication capabilities.
These sensors can be expended at a much lower cost and are capable of detecting
conditions such as temperature, sound, security or any other system. A good
protocol design should be able to scale well both in energy heterogeneous and
homogeneous environment, meet the demands of different application scenarios
and guarantee reliability. On this basis, we have compared six different
protocols of different scenarios which are presenting their own schemes of
energy minimizing, clustering and route selection in order to have more
effective communication. This research is motivated to have an insight that
which of the under consideration protocols suit well in which application and
can be a guide-line for the design of a more robust and efficient protocol.
MATLAB simulations are performed to analyze and compare the performance of
LEACH, multi-level hierarchal LEACH and multihop LEACH.Comment: NGWMN with 7th IEEE Inter- national Conference on Broadband and
Wireless Computing, Communication and Applications (BWCCA 2012), Victoria,
Canada, 201
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