Abstract:
Copying information is an elementary operation in classical information processing. However, copying seems rather different in the quantum regime. Since the discovery of the universal quantum cloning machine, much has been found from the fundamental point of view about quantum copying. But a basic question as to the utility of universal quantum cloning remains. We have considered its application in quantum state restoration by using cloning circuit for state estimation. It might be expected that classical information from the state estimation might help restore the quantum state that was disturbed during transmission. We find that the fidelity of the final state is, interestingly, independent of error probabilities inside the channel. However, this also turns out to impose a severe constraint on our original aims.

Abstract:
Universal quantum cloning machines (UQCMs), sometimes called quantum cloners, generate many outputs with identical density matrices, with as close a resemblance to the input state as is allowed by the basic principles of quantum mechanics. Any experimental realization of a quantum cloner has to cope with the effects of decoherence which terminate the coherent evolution demanded by a UQCM. We examine how many clones can be generated within a decoherence time. We compare the time that a quantum cloner implemented with trapped ions requires to produce $M$ copies from $N$ identical pure state inputs and the decoherence time during which the probability of spontaneous emission becomes non-negligible. We find a method to construct an $N\to M$ cloning circuit, and estimate the number of elementary logic gates required. It turns out that our circuit is highly vulnerable to spontaneous emission as the number of gates in the circuit is exponential with respect to the number of qubits involved.

Abstract:
There is an increasing interest in the relation between the solar activity and
climate change. As for the solar activity, a fractal property of the sunspot
number was studied by many works. In general, a fractal property was observed
in the time series of dynamics of complex systems. The purposes of this
study are to investigate the relations among the solar activity, total ozone,
Quasi-Biennial Oscillation (QBO), the North Atlantic Oscillation (NAO), and El
Ni?o-Southern Oscillation (ENSO) from a view of multi-fractality. To detect the changes of multifractality, we examined the multifractal
analysis on the time series of the solar 10.7-cm radio flux (F10.7 flux), total
ozone, QBO, NAO, and Ni?o3.4 indices. During the period 1950
and 2010, for the F10.7 flux and QBO index, the matching in monofractality or
multifractality is observed and the increase and decrease of multifractality is
similar; that is the change of multifractality is similar. In the same way, it is very similar, during the period 1985 and 2010, for the QBO and the total ozone, and during the period 1950 and 2010, for the QBO, and NAO and for the QBO, and Ni?o3.4. Compared to Ni?o3.4, the multifractality of NAO and QBO was strong and it
turns out that they are undergoing unstable change.

Abstract:
Atmospheric concentrations of greenhouse gases are rising, leading to a positive
radiative forcing of climate and an expected warming of surface temperatures.
In general, fractal properties may be observed in the time series of the
dynamics of complex systems. To study the relation between the atmospheric
CO_{2} concentration and the climate indices, we investigated the change of
fractal behavior of the CO_{2}, the carbon isotope ratio (δ^{13}C) of atmospheric
CO_{2}, the El Ni？o-Southern Oscillation (ENSO), the Pacific Decadal Oscillation
(PDO), and the North Atlantic Oscillation (NAO) indices using the multifractal
analysis. When the atmospheric CO_{2} growth rate was large, the multifractality
of CO_{2}, δ^{13}C in CO_{2}, ENSO, and NAO was large and the changes
were large from the change of fractality. The changes of CO_{2} and ENSO were
closely related and the influence of the CO_{2} on the ENSO was strong from the
change in fractality and wavelet coherence. When the El Ni？o occurred, the
CO_{2} growth rate was large. The CO_{2} related to PDO, NAO, and global temperature
from the change in fractality and wavelet coherence. Especially, the
changes of CO_{2} and global temperature were closely related. When the global
warming hiatus occurred, the multifractality of the global temperature was
weaker than that of CO_{2} and the change of the global temperature was stable.
These findings will contribute to the research of the relation between the atmospheric
CO_{2} and climate change.

There is increasing interest in
finding the relation between the sunspot number (SSN) and solar polar field. In
general, fractal properties may be observed in the time series of the dynamics
of complex systems, such as solar
activity and climate. This study investigated the relations between the SSN and solar
polar field by performing a multifractal analysis. To investigate the change in
multifractality, we applied a wavelet transform to time series. When the SSN was maximum and minimum, the SSN showed monofractality or
weak multifractality. The solar polar field showed weak multifractality when
that was maximum and minimum. When the SSN became maximum, the fractality of
the SSN changed from multifractality to monofractality. The multifractality of
SSN became large before two years of SSN maximum, then
that of the solar polar field became large and changed largely. It was found
that the change in SSN triggered the change in the solar polar field. Hence,
the SSN and solar polar field were closely correlated from the view point of fractals. When the maximum
solar polar field before the maximum SSN was larger, the maximum SSN of the
next cycle was larger. The formation of the magnetic field of the sunspots was
correlated with the solar polar field.

Abstract:
We investigate the inclinations of heliospheric current sheet at two sites in interplanetary space, which are generated from the same solar source. From the data of solar wind magnetic fields observed at Venus (0.72 AU) and Earth (1 AU) during December 1978-May 1982 including the solar maximum of 1981, 54 pairs of candidate sector boundary crossings are picked out, of which 16 pairs are identified as sector boundaries. Of the remainder, 12 pairs are transient structures both at Venus and Earth, and 14 pairs are sector boundaries at one site and have transient structures at the other site. It implies that transient structures were often ejected from the coronal streamer belt around the solar maximum. For the 16 pairs of selected sector boundaries, we determine their normals by using minimum variance analysis. It is found that most of the normal azimuthal angles are distributed between the radial direction and the direction perpendicular to the spiral direction both at Venus and Earth. The normal elevations tend to be smaller than ~ 45° with respect to the solar equatorial plane, indicating high inclinations of the heliospheric current sheet, in particular at Earth. The larger scatter in the azimuth and elevation of normals at Venus than at Earth suggests stronger effects of the small-scale structures on the current sheet at 0.72 AU than at 1 AU. When the longitude difference between Venus and Earth is small (<40° longitudinally), similar or the same inclinations are generally observed, especially for the sector boundaries without small-scale structures. This implies that the heliospheric current sheet inclination tends to be maintained during propagation of the solar wind from 0.72 AU to 1 AU. Detailed case studies reveal that the dynamic nature of helmet streamers causes variations of the sector boundary structure. Key words. Interplanetary physics (interplanetary magnetic fields; sources of solar wind)

Abstract:
We study the nuclear stopping in high energy nuclear collisions using the constituent quark model. It is assumed that wounded nucleons with different number of interacted quarks hadronize in different ways. The probabilities of having such wounded nucleons are evaluated for proton-proton, proton-nucleus and nucleus-nucleus collisions. After examining our model in proton-proton and proton-nucleus collisions and fixing the hadronization functions, it is extended to nucleus-nucleus collisions. It is used to calculate the rapidity distribution and the rapidity shift of final state protons in nucleus-nucleus collisions. The computed results are in good agreement with the experimental data on $^{32}\mbox{S} +\ ^{32}\mbox{S}$ at $E_{lab} = 200$ AGeV and $^{208}\mbox{Pb} +\ ^{208}\mbox{Pb}$ at $E_{lab} = 160$ AGeV. Theoretical predictions are also given for proton rapidity distribution in $^{197}\mbox{Au} +\ ^{197}\mbox{Au}$ at $\sqrt{s} = 200$ AGeV (BNL-RHIC). We predict that the nearly baryon free region will appear in the midrapidity region and the rapidity shift is $\langle \Delta y \rangle = 2.22$.

Abstract:
Quantum correlation, or entanglement, is now believed to be an indispensable physical resource for certain tasks in quantum information processing, for which classically correlated states cannot be useful. Besides information processing, what kind of physical processes can exploit entanglement? In this paper, we show that there is indeed a more basic relationship between entanglement and its usefulness in thermodynamics. We derive an inequality showing that we can extract more work out of a heat bath via entangled systems than via classically correlated ones. We also analyze the work balance of the process as a heat engine, in connection with the Second Law of thermodynamics.

Abstract:
We study the effect of a phase shift on the amount of transferrable two-spin entanglement in a spin chain. We consider a ferromagnetic Heisenberg/XY spin chain, both numerically and analytically, and two mechanisms to generate a phase shift, the Aharonov-Casher effect and the Dzyaloshinskii-Moriya interaction. In both cases, the maximum attainable entanglement is shown to be significantly enhanced, suggesting its potential usefulness in quantum information processing.

Abstract:
The Fano-Kondo effect in zero-bias conductance is studied based on a theoretical model for the T-shaped quantum dot by the finite temperature density matrix renormalization group method. The modification of the two Fano line shapes at much higher temperatures than the Kondo temperature is also investigated by the effective Fano parameter estimated as a fitting parameter.