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Aug 29 (Mon) |
Aug 30 (Tue) |
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10:00-10:50 Archan S. Majumdar (Bose
National Centre for Basic Sciences) “Quantum entanglement and dark energy of the universe” |
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10:50-11:10 Coffee Break |
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11:10-12:00 Akio Hosoya (Tokyo Institute of Technology) “Weak Value and Born's Rule” |
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Lunch |
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2:30-3:20 Kentaro Somiya (Tokyo Institute of
Technology) “ Quantum-noise reduction technique in a gravitational-wave detector” |
2:00-2:50 Doyeol Ahn (University of
Seoul) “General relativistic issues on Quantum Information: Non-uniform Hawking decay and Cloning theorem” |
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3:20-4:10 Atsushi Nishizawa (Kyoto university) “ Application of weak measurement to gravitational-wave detection” |
2:50-3:40 Jae-Weon
Lee (Jungwon Univ.) “Gravity and quantum mechanics emerging from information loss” |
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4:10-4:30 Coffee Break |
3:40-4:00
Coffee Break |
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4:30-5:20 Charles Bennett (IBM, Yorktown Heights) "Black hole information budget in the random unitary model" |
4:00-4:30 Yutaka Shikano (Tokyo Institute of Technology) “On the troubles of entanglement in the cosmological setting” |
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5:20-5:50 Maurice van Putten (KIAS) “ Entropic force in black hole binaries” |
4:30-5:00 Takumi Mori (University
of Tokyo) “Ponderomotive squeezing experiment for gravitational wave detectors” |
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5:50-6:20 Taeseung Choi (Seoul Women's University) “Relativistic effects on the spin of a
massive Dirac particle under Lorentz Transformation” |
5:00-5:30 Dong-Hoon Kim (IEU) “Information Geometric Modeling of Scattering
Induced Quantum Entanglement - analysis in analogy to gravitation” |
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5:30 Closing |
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6:00 Banquet |
Abstracts
Invited
talks
Akio Hosoya (Tokyo Institute of Technology)
“Weak Value and Born's Rule”
In the conventional Copenhagen interpretation of quantum mechanics, the
value of physical quantity emerges
only after measurement but
not before. However, the idea of value only after measurement becomes problematic when one
considers quantum gravity, because measurements presuppose spacetime
which emerges after the quantum era
of the Universe apart from
the fact that there are no observers
who can make projective measurements of the Universe.
We characterize a value of
an observable by a `sum rule' for generally non-commuting observables and a
`product rule'
when restricted to a maximal commuting subalgebra of observables
together with the requirement that the value is unity
for the projection
operator of the prepared state and
the values are zero for the projection operators of the states
which are orthogonal to the
prepared state. The crucial requirement is that the expectation value and the
variance
of an observable should be
independent of the way of measurement, i.e., the choice of the maximal
commuting
subalgebra of
observables. We shall call the
value a `contextual value'. We show that the contextual value of an observable
coincides with the weak
value advocated by Aharonov and his colleagues by demanding the consistency of quantum mechanics
with Kolmogorov's measure
theory of probability. This also gives a derivation of Born's rule, which is
one of the axioms of conventional
quantum mechanics.
arXiv:1104.1873
Atsushi Nishizawa (Kyoto university)
“Application of weak measurement to gravitational-wave
detection”
Recently, weak measurement has been paid much attention in the fields
of
quantum measurement and quantum information. The interesting features
are that a measured system is weakly perturbed so that the back-action
noise is negligible, and that the measurement value is amplified beyond
the eigenvalues of an observable. Although there are several
experimental demonstrations of the weak measurement, the practical
advantage is still unclear. In this presentation, we apply the weak
measurement to an optical phase estimation, especially focusing on the
detection of gravitational waves.
Charles Bennett (IBM, Yorktown Heights)
"Black hole information budget in the random unitary model"
Doyeol Ahn (University of Seoul)
"General relativistic issues on Quantum Information:
Non-uniform Hawking decay and Cloning theorem "
The effect of a
black hole state evolution on the Hawking radiation is studied
using the final
state boundary condition. It is found that thermodynamic or statistical
mechanical
properties of a
black hole depend strongly on the unitary evolution operator S which determines
the black hole
state evolution. When the operator S is random unitary or pseudo random
unitary,
a black hole emits
thermal radiation as predicted by Hawking three decades ago.
On the other hand,
it is found that the emission of Hawking radiation could be suppressed
when the evolution
of a black hole state is given by the generator of the coherent state.
As a second topic,
potential implications of closed
timelike curves (CTCs) on quantum information
will be discussed.
One can ask fundamental questions about what is physically possible and what is
not.
An example is the
“no cloning theorem” in quantum mechanics, which states that
no physical means
exists by which an unknown arbitrary quantum state can be reproduced
or copied
perfectly. Using the Deutsch approach, we found that this theorem can be
circumvented in
the presence of closed timelike curves, allowing the cloning of an unknown
arbitrary quantum
state chosen from a finite alphabet of states.
Since the
“no cloning theorem” has played a central role in the development
of
quantum
information science, it is clear that the existence of CTCs would radically
change
the rules for
quantum information technology.
Nevertheless we
show that this type of cloning does not violate no-signalling criteria.
Kentaro Somiya (Tokyo Institute of Technology)
“Quantum-noise reduction technique in a gravitational-wave
detector”
First-generation gravitational-wave detectors including LIGO in the US,
Virgo and GEO in Europe, and TAMA in Japan have achieved the
sensitivity
as high as 1e-19 m/rtHz in the spectrum, and second-generation
detectors
will achieve a sensitivity even 10 times higher. The detectors will
then
encounter the quantum limit determined by the Heisenberg's Uncertainty
Principle. It is however possible to circumvent the limit in various
ways
that have been theoretically developed since 1960's. In this
presentation,
we will introduce some of the so-called quantum non-demolition
techniques,
which are to be implemented in the second-generation gravitational-wave
detectors to improve the sensitivity.
Jae-Weon Lee (Jungwon univ.)
“Gravity and quantum mechanics from information loss”
It is suggested
that quantum mechanics and gravity are not fundamental but emerge
from information
loss at causal horizons such as Rindler horizons or event horizons.
The loss of
information about the fields inside the horizons seen by an outside observer
corresponds to
maximizing Shannon entropy of the field configuration, which leads to the
conventional
quantum partition function for the field
and the first law of thermodynamics (dE=TdS) for gravitational systems.
Quantum randomness, entropic gravity, the
Einstein equation and even the holographic principle are shown to
arise naturally in
this formalism. Implications for
dark energy and quantum entanglement are also discussed.
Information loss at causal horizons seems
to be one of the roots of all physics.
(Found.Phys.41:744 & arXiv:1107.3448)
Archan S. Majumdar (Bose National Centre for Basic Sciences)
"Quantum entanglement and dark energy of the universe"
We explore two observable consequences of quantum entanglement in
the paradigm of cosmology. For both of these, the respective mechanisms
lead
to the emergence of dark energy of the universe, a form of energy which
dominates the energy density of our present universe and whose negative
pressure ensures the observed acceleration. Our first approach stems
from
dynamical wave function collapse models in which a fluctuating
background
scalar field interacting with the matter wave-function causes the
collapse
of the latter through non-linear stochastic terms in the Schrodinger
equation.
This process is accompanied by a continuous liberation of energy by the
scalar
field at a specified rate. The wave-function collapse of dark matter
particles
results in the liberated accumulated energy to constitute the requisite
amount
of dark energy around the time of galaxy formation and can cause the
universe
to accelerate at later times. The second approach concerns possible
relics of
the QCD phase transition, which are the so-called strange quark nuggets
(SQNs). The fact that the colour degrees of freedom are inaccessible to
any
observer outside the SQN surface leads to an entanglement entropy. By
the
holographic mechanism, this leads to the formation of entanglement energy.
We
show that this entanglement energy could constitute the required amount
of
dark energy which dominates the current energy density of the universe
leading to the observed late-time acceleration of the universe.
Observational
results are used to place constraints on our model parameters. A
general
comparison with other standard approaches of dark energy, e.g., scalar
field models, points out the relative merits and drawbacks of the
entanglement based schemes.
Contributed
talks
Yutaka Shikano (Tokyo
Institute of Technology)
“On the troubles of entanglement in the
cosmological setting”
We discuss how to verify the existence of the quantum correlation in the
cosmological setting,
the early universe context. We strikingly point out that the well-known
entanglement criteria in
quantum information cannot be directly applied to this.
Takumi MORI (GSFS, the university of Tokyo)
“Ponderomotive
squeezing experiment for gravitational wave detectors”
The quantum
radiation pressure noise (RPN) of a laser interferometer, which comes from the
number fluctuation
of photons of
laser light at the Heisenberg limit, has not been observed yet. This
fluctuation can be correlated with the phase
fluctuation of light when the light hits
a mirror.
RPN can be reduced
by measuring this phenomenon which we call ponderomotive squeezing. This would
be quite important
technique for
future gravitational wave detectors.
In order to
observe RPN and reduce it on a table-top experiment in advance to full-scale
gravitational wave detectors, we are developing the laser interferometer with Fabry-Perot cavities with very
special, small suspended mirrors. The mass of the small mirror is 20mg,
and the target
frequency range to observe RPN is 300Hz-1kHz. The detail of this experiment will be
presented.
Dong-Hoon Kim (IEU)
“Information Geometric Modeling of Scattering Induced Quantum
Entanglement - analysis in analogy to gravitation.”
In this work, we present an information geometric analysis of
entanglement generated by an s-wave scattering between two
Gaussian wave packets. We
conjecture that the pre and post-collisional quantum dynamical scenarios
related to an elastic
head-on collision are
macroscopic manifestations emerging from microscopic statistical structures.
We then describe them by uncorrelated and correlated Gaussian
statistical models, respectively. Via information geometric analysis,
we investigate the effects of micro-correlations on the evolution of
maximal probability paths on statistical manifolds induced by systems
whose microscopic degrees
of freedom are Gaussian distributed. This analysis allows us to express the
entanglement strength in
terms of scattering potential and incident particle energies.
Furthermore, we obtain exact expressions for the information geometric analogue
of standard indicators of chaos such as the sectional curvatures,
Jacobi field intensities and the Lyapunov exponents. Finally,
we present an analytical
estimate of the information geometric entropy - a suitable measure that quantifies
the complexity
of geodesic paths on curved manifolds, and discuss the relation between
entanglement and information geometric entropy.
Maurice van Putten (KIAS)
“Entropic force in black hole binaries”
We derive the static
entropic force in black hole binaries by Gibbs' principle from the
Bekenstein-Hawking entropy of
trapped surfaces in time-symmetric initial data. The corresponding
dynamical equations of motion follow from a new adiabatic
variational principle in the presence of trapped surfaces. Newton's law
follows from the large separation limit, while new scaling
laws are derived for the
entropy jump in the formation of a common horizon envelope in a merger. This
formulation satisfies monotonicity
of entropy as a function of separation, whereby the entropic force is
always attractive, and the Bekenstein entropy bound.
Holographic embeddings using time like surfaces of constant redshift do
not satisfy monotonicity, and satisfy the Bekenestein entropy
bound only by including entropy
rich dark matter of unknown origin. (arXiv:1107.1764)
Taeseung Choi * (Seoul Women's University),
Jin Hur and Jaewan Kim (KIAS)
“Relativistic effects on the spin of a massive Dirac particle
under Lorentz
Transformation”
We have studied the relativistic effect on the spin of a massive Dirac
particle under an arbitrary
Lorentz transformation. We have used a relativistic spin as the
Foldy-Woutheysen(FW) mean spin
which is known to be the same as the center of mass spin. Using the FW
representation we have
removed the ambiguity which is originated from the entanglement between
the momentum and
the spin. As a result we have clarified the ambiguity in the
relativistic properties of quantum
entanglement between the spins of a pair of massive Dirac particels. We
also have shown moving
observers obtain the consistent monotonic behavior between the
concurrence of the spin states of a
pair and the maximum value of Bell parameter in Bell's inequality.