823 research outputs found
Classical Analogue of Weak Value in Stochastic Process
One of the remarkable notions in the recent development of quantum physics is
the weak value related to weak measurements. We emulate it as a two-time
conditional expectation in a classical stochastic model. We use the well known
symmetrized form of the master equation, which is formally equivalent to the
wave equation in quantum mechanics apart from the fact that wave functions are
always real. The origin of the unusual behaviors of the weak value such as the
negative probability and the abnormal enhancement of some expectations becomes
clearer in the present case, where the two-time conditional probability has no
ambiguity of imaginary/complex values.Comment: Revised version from Arxiv:1109.4302. To appear in the proceedings of
the Symposium on 'Interface between Quantum Information and Statistical
Physics', to be published by World Scientifi
An Explicit Form of the Equation of Motion of the Interface in Bicontinuous Phases
The explicit form of the interface equation of motion derived assuming a
minimal surface is extended to general bicontinuous interfaces that appear in
the diffusion limited stage of the phase separation process of binary mixtures.
The derivation is based on a formal solution of the equivalent simple layer for
the Dirichlet problem of the Laplace equation with an arbitrary boundary
surface. It is shown that the assumption of a minimal surface used in the
previous linear theory is not necessary, but its bicontinuous nature is the
essential condition required for us to rederive the explicit form of the simple
layer. The de- rived curvature flow equation has a phenomenological cut-off
length, i.e., an `electro-static' screening length. That is re- lated to the
well-known scaling length characterizing the spatial pattern size of a
homogeneously growing bicontinuous phase. The corresponding equation of the
level function in this scheme is given in a one-parameter form also.Comment: 18 page
Irreversible Circulation of Fluctuation and Entropy Production
Physical and chemical stochastic processes described by the master equation
are investigated. In this paper, we examine the entropy production both for the
master equation and for the corresponding Fokker-Planck equation. For the
master equation, the exact expression of the entropy production was recently
derived by Gaspard using the Kolmogorov-Sinai entropy ({\em J.Stat.Phys.},
\textbf{117} (2004), 599; [Errata; \textbf{126} (2006), 1109 ]). Although
Gaspard's expression is derived from a stochastic consideration, it should be
noted that Gaspard's expression conincides with the thermodynamical expression.
For the corresponding Fokker-Planck equation, by using the detailed imbalance
relation which appears in the derivation process of the fluctuation theorem
through the Onsger-Machlup theory, the entropy production is expressed in terms
of the {\em irreversible circulation of fluctuation}, which was proposed by
Tomita and Tomita ({\em Prog.Theor.Phys.}, \textbf{51} (1974), 1731). However,
this expression for the corresponding Fokker-Planck equation differs from that
of the entropy production for the master equation. This discrepancy is due to
the difference between the master equation and the corresponding Fokker-Planck
equation, namely the former treats discrete events, but the latter equation is
an approximation of the former one. In fact, in the latter equation, the
original discrete events are smoothed out. To overcome this difficulty, we
propose the {\em path weight principle}. By using this principle, the modified
expression of the entropy production for the corresponding Fokker-Planck
equation coincides with that of the master equation (i.e., the thermodynamical
expression) for a simple chemical reaction system and a diffusion system.Comment: 17pages, no figures, to appear in Progreess of Theoretical Physics,
Vol. 119, No.
Recovery in quantum error correction for general noise without measurement
It is known that one can do quantum error correction without syndrome
measurement, which is often done in operator quantum error correction (OQEC).
However, the physical realization could be challenging, especially when the
recovery process involves high-rank projection operators and a superoperator.
We use operator theory to improve OQEC so that the implementation can always be
done by unitary gates followed by a partial trace operation. Examples are given
to show that our error correction scheme outperforms the existing ones in
various scenarios.Comment: 10 page
Metamaterials with magnetism and chirality
This review introduces and overviews electromagnetism in structured metamaterials which undergo simultaneous time-reversal and space-inversion symmetry breaking due to magnetism and chirality. Direct experimental observation of optical magnetochiral effects in a single metamolecule with magnetism and chirality is demonstrated at microwave frequencies. Numerical simulations based on a finite element method reproduce the experimental results well, and predict the emergence of giant magnetochiral effects, by combining resonances in the metamolecule. Toward the realization of magnetochiral effects at higher frequencies than microwaves, a metamolecule is miniaturized in the presence of ferromagnetic resonance in a cavity and coplanar waveguide. This work opens the door to the realization of a one-way mirror and synthetic gauge fields for electromagnetic waves
Calibration of AGN Reverberation Distance Measurements
In Yoshii et al. (2014), we described a new method for measuring
extragalactic distances based on dust reverberation in active galactic nuclei
(AGNs), and we validated our new method with Cepheid variable stars. In this
paper, we validate our new method with Type Ia supernovae (SNe Ia) which
occurred in two of the AGN host galaxies during our AGN monitoring program: SN
2004bd in NGC 3786 and SN 2008ec in NGC 7469. Their multicolor light curves
were observed and analyzed using two widely accepted methods for measuring SN
distances, and the distance moduli derived are for SN
2004bd and for SN 2008ec. These results are used to obtain
independently the distance measurement calibration factor, . The value
obtained from the SN Ia discussed in this paper is
which matches, within the range of 1 uncertainty, , previously calculated ab initio in Yoshii et al. (2014). Having
validated our new method for measuring extragalactic distances, we use our new
method to calibrate reverberation distances derived from variations of H
emission in the AGN broad line region (BLR), extending the Hubble diagram to
where distinguishing between cosmologies is becoming possible.Comment: Astrophysical Journal Letters accepte
Variation of Inner Radius of Dust Torus in NGC4151
The long-term optical and near infrared monitoring observations for a type 1
act ive galactic nucleus NGC 4151 were carried out for six years from 2001 to
2006 b y using the MAGNUM telescope, and delayed response of flux variations in
the band to those in the band was clearly
detected. Based on cross correlation analysis, we precisely measured a lag time
for eight separate periods, and we found that is not
constant changing be tween 30 and 70 days during the monitoring period. Since
is the ligh t travel time from the central energy source out to the
surrounding dust torus, this is the first convincing evidence that the inner
radius of dust torus did ch ange in an individual AGN. In order to relate such
a change of with a change of AGN luminosity , we presented a
method of taking an average of th e observed -band fluxes that corresponds
to the measured value of , and we found that the time-changing track
of NGC 4151 in the versus diagram during the monitoring period
deviates from the relation of expected from dust
reverberation. This result, combined with t he elapsed time from period to
period for which was measured, indicat es that the timescale of dust
formation is about one year, which should be taken into account as a new
constraint in future studies of dust evolution in AGNs.Comment: 5 pages, 3 figures, To appear in the ApJ Lette
JHK' Imaging Photometry of Seyfert 1 AGNs and Quasars I: Multi-Aperture Photometry
Near-infrared imaging photometry was obtained of 331 AGNs consisting
mainly of Seyfert 1 AGNs and quasars (QSOs). This sample was selected to cover
a range of radio emission strength, redshift from to 1, and absolute
-magnitude from mag to -18 mag. Among low- AGNs with ,
Seyfert AGNs are distributed over a region from a location typical of
``galaxies'' to a location typical of ``QSOs'' in the two-color to
diagram, but Seyfert AGNs are distributed around the location of
``galaxies''. Moreover, bright AGNs with respect to absolute -magnitude are
distributed near the location of ``QSOs'', while faint AGNs are near the
location of ``galaxies''. The distribution of such low- AGNs in this diagram
was found to have little dependence on their 6 cm radio flux. The near-infrared
colors of the AGNs observed with an aperture of 7 pixels () are more
QSO-like than those observed with larger apertures up to 15 pixels ().
This aperture effect may be explained by contamination from the light of host
galaxies within larger apertures. This effect is more prominent for less
luminous AGNs
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