4,462 research outputs found

### Quantum Logic Processor: A Mach Zehnder Interferometer based Approach

Quantum Logic Processors can be implemented with Mach Zehnder
Interferometer(MZI) configurations for the Quantum logic operations and gates.
In this paper, its implementation for both optical and electronic system has
been presented. The correspondence between Jones matrices for photon
polarizations and Pauli spin matrices for electrons gives a representation of
all the unitary matrices for the quantum gate operations. A novel quantum
computation system based on a Electronic Mach Zehnder Interferometer(MZI) has
also been proposed. It uses the electron spin as the primary qubit. Rashba
effect is used to create Unitary transforms on spin qubits. A mesoscopic Stern
Gerlach apparatus can be used for both spin injection and detection. An
intertwined nanowire design is used for the MZI. The system can implement all
single and double qubit gates. It can easily be coupled to form an array. Thus
the Quantum Logic Processor (QLP) can be built using the system as its
prototype.Comment: 19 pages, 6 figures, 8 Table

### Energy dependent wavelength of the ion induced nanoscale ripple

Wavelength variation of ion beam induced nanoscale ripple structure has
received much attention recently due to its possible application in
nanotechnology. We present here results of Ar$^+$ bombarded Si in the energy
range 50 to 140 keV to demonstrate that with beam scanning the ripple
wavelength increases with ion energy and decreases with energy for irradiation
without ion beam scanning. An expression for the energy dependence of ripple
wavelength is proposed taking into simultaneous effect of thermally activated
surface diffusion and ion induced effective surface diffusion.Comment: REVTeX (4 pages), 3 EPS figure

### Search for optical bursts from the gamma ray burst source GBS 0526-66

Attempts were made to detect optical bursts from the gamma-ray burst source GBS 0526-66 during Dec. 31, 1984 to Jan. 2, 1985 and Feb. 23 to Feb. 24, 1985, using the one meter reflector of the Kavalur Observatory. Jan. 1, 1985 coincided with the zero phase of the predicted 164 day period of burst activity from the source (Rothschild and Lingenfelter, 1984). A new optical burst photon counting system with adjustable trigger threshold was used in parallel with a high speed photometer for the observations. The best time resolution was 1 ms and maximum count rate capability was 255,000 counts s(-1). Details of the instrumentation and observational results are presented

### Pion and Kaon dissociation in hot quark medium

Pion and kaon dissociation in a medium of hot quark matter is studied in the
Nambu Jona-Lasinio model. The decay width of pion and kaon are found to be
large but finite at temperatures much higher than the so called critical
temperature of chiral or deconfinement transition, kaon decay width being
larger. Consequently, pions and even kaons (with a lower density compared to
pions) should coexist with quarks and gluons at such high temperatures. The
implication of the above result in the study of Quark-Gluon plasma is
discussed.Comment: Latex file with one postscript fil

### The holographic fluid dual to vacuum Einstein gravity

We present an algorithm for systematically reconstructing a solution of the
(d+2)-dimensional vacuum Einstein equations from a (d+1)-dimensional fluid,
extending the non-relativistic hydrodynamic expansion of Bredberg et al in
arXiv:1101.2451 to arbitrary order. The fluid satisfies equations of motion
which are the incompressible Navier-Stokes equations, corrected by specific
higher derivative terms. The uniqueness and regularity of this solution is
established to all orders and explicit results are given for the bulk metric
and the stress tensor of the dual fluid through fifth order in the hydrodynamic
expansion. We establish the validity of a relativistic hydrodynamic description
for the dual fluid, which has the unusual property of having a vanishing
equilibrium energy density. The gravitational results are used to identify
transport coefficients of the dual fluid, which also obeys an interesting and
exact constraint on its stress tensor. We propose novel Lagrangian models which
realise key properties of the holographic fluid.Comment: 31 pages; v2: references added and minor improvements, published
versio

### Probing the superconducting ground state of ZrIrSi: A $\mu$SR study

The superconducting ground state of newly reported ZrIrSi is probed by means
of $\mu$SR technique along with resistivity measurement. The occurrence of
superconductivity at $T_\mathrm{C}$ = 1.7 K is confirmed by resistivity
measurement. ZF-$\mu$SR study revealed that below $T_\mathrm{C}$, there is no
spontaneous magnetic field in the superconducting state, indicates TRS is
preserved in case of ZrIrSi. From TF-$\mu$SR measurement, we have estimated the
superfluid density as a function of temperature, which is described by an
isotropic $s-$wave model with a superconducting gap
$2\Delta(0)/k_\mathrm{B}T_\mathrm{C}$ = 5.1, indicates the presence of strong
spin-orbit coupling. {\it Ab-initio} electronic structure calculation indicates
that there are four bands passing through the Fermi level, forming four Fermi
surface pockets. We find that the low-energy bands are dominated by the
$4d$-orbitals of transition metal Zr, with substantially lesser weight from the
$5d$-orbitals of the Ir-atoms.Comment: 6 pages, 4 figure

### Investigation of Superconducting Gap Structure in HfIrSi using muon spin relaxation/rotation

Appearance of strong spin-orbit coupling (SOC) is apparent in ternary
equiatomic compounds with 5$d$-electrons due to the large atomic radii of
transition metals. SOC plays a significant role in the emergence of
unconventional superconductivity. Here we examined the superconducting state of
HfIrSi using magnetization, specific heat, zero and transverse-field (ZF/TF)
muon spin relaxation/rotation ($\mu$SR) measurements. Superconductivity is
observed at $T_\mathrm{C}$ = 3.6 K as revealed by specific heat and
magnetization measurements. From the TF$-\mu$SR analysis it is clear that
superfluid density well described by an isotropic BCS type $s$-wave gap
structure. Furthermore, from TF$-\mu$SR data we have also estimated the
superconducting carrier density $n_\mathrm{s}$ = 6.6 $\times$10$^{26}$m$^{-3}$,
London penetration depth $\lambda_{L}(0)$ = 259.59 nm and effective mass
$m^{*}$ = 1.57 $m_{e}$. Our zero-field muon spin relaxation data indicate no
clear sign of spontaneous internal field below $T_\mathrm{C}$, which implies
that the time-reversal symmetry is preserved in HfIrSi. Theoretical
investigation suggests Hf and Ir atoms hybridize strongly along the $c$-axis of
the lattice, which is responsible for the strong three-dimensionality of this
system which screens the Coulomb interaction. As a result despite the presence
of correlated $d$-electrons in this system, the correlation effect is weakened,
promoting electron-phonon coupling to gain importance.Comment: 8 pages, 4 figure

### Diffusion with rearranging traps

A model for diffusion on a cubic lattice with a random distribution of traps
is developed. The traps are redistributed at certain time intervals. Such
models are useful for describing systems showing dynamic disorder, such as
ion-conducting polymers. In the present model the traps are infinite, unlike an
earlier version with finite traps, this model has a percolation threshold. For
the infinite trap version a simple analytical calculation is possible and the
results agree qualitatively with simulation.Comment: Latex, five figure

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