



Program 

Registration: 10 Sep. afternoon and 11
Sep. 8:009:00 at Hotel Parmis. 



14 Sep. 

13 Sep. 

12 Sep. 

11 Sep. 

Mikio Nakahara 
9:30 
Saverio Pascazio 
9:30 
Luiz Davidovich 
9:30 
Vlatko Vedral 
9:30 
break 
10:15 
ShaoMing Fei 
10:15 
Marcos de Oliveira 
10:25 
Dan Browne 
10:25 
Patrick Hayden 
10:30 
Francesco Ciccarello 
10:40 
break 
11:00 
break 
11:00 


break 
11:05 
Dagmar Bruss 
11:30 
Chiara Macchiavello 
11:30 


Tom Stace 
11:30 
Faisal Khan 
12:15 
Zahra Shadman 
12:15 


Sean Barrett 
12:05 
lunch 
12:40 
lunch 
12:40 


lunch 
12:40 
Mahmoud AbdelAty 
14:30 
Seyed Javad Akhtarshenas 
14:30 


Ali A. Kamli 
14:30 
Ugo Marzolino 
15:05 
Abolfazl Bayat 
15:05 


Nigum Arshed 
15:05 
Yasushi Kondo 
15:30 
Daniel Burgarth 
15:30 


break 
15:30 
break 
15:55 
break 
15:55 


poster session 
16:0018:30 
Abdollah Langari 
16:30 
Hubert de Guise 
16:30 




Archan S. Majumdar 
17:05 
Akira SaiToh 
17:05 


Abstractplenary talks: 
Davidovich, Luiz: From Einstein and Schrodinger
to Quantum Optics Experiments
This talk reviews recent theoretical and experimental findings on the
opensystem dynamics of entanglement, which can differ in remarkable ways
from the dynamics of the individual components of the system. Decoherence
leads to nonexponential decay of entanglement, which may vanish even when
coherence is still present in the system. These results, which have been
recently probed by quantum optics experiments, are relevant for assessing
the robustness of applications like quantum communication and computation,
as well as for addressing fundamental questions, already raised by Einstein
and Schrodinger, concerning the classical limit of quantum mechanics. 
Hayden, Patrick:
Quantum information theory as asymptotic geometry
Quantum states are represented as vectors in an inner product space. Because
the dimension of that state space grows exponentially with the number of its
constituents, quantum information theory is in large part the asymptotic
theory of finite dimensional inner product spaces. I'll highlight some
examples of how abstract mathematical results on low distortion embeddings
of normed spaces manifest themselves in quantum information theory as
improvements on the famous "teleportation" procedure, reductions in the
amount of shared secret information required to encrypt a quantum message,
and counterexamples to the additivity conjecture, among many other
applications. 
Vedral, Vlatko:
Quo Vadis Quantum Information?
I will talk about three recent developments in quantum information that I
think will leave a longterm legacy on science in general. The first is
centered on quantum simulations of complex physical systems. The second is
regarding the role of quantum coherence in living systems. The third is our
emerging, informationbased, understanding of the quantum nature of reality.
The importance of each of these directions goes well beyond the narrowly
defined goal of making faster algorithms, though that goal itself is also
worth pursuing. I will speak about concrete open problems within each of
these three areas and review some of the key recent findings. 
Abstractkeynote talks: 
Bruß,
Dagmar:
A
brief visit to the zoo of multipartite entangled states
Entanglement is one of the most fascinating features of quantum mechanics
and plays a central role in quantum information processing. Genuine
multipartite entanglement comes in various species that populate a rich zoo.
In this talk we will visit two less wellknown members of this zoo: first,
the ``phased Dicke states''. Here, a method for their detection will be
explained which uses witness operators that are related to diffractive
properties. Second, we will study the ``real equally weighted states'' which
appear in quantum algorithms. Here, we will answer the question whether most
states of this family are indeed multipartite entangled. 
Macchiavello, Chiara: Violation of the
generalized quantum Hamming bound in quantum error correction with
correlated noise
The question of whether the quantum Hamming bound, which quantifies the
minimum resources needed in order to achieve successful quantum error
correction for nondegenerate codes, can be violated with degenerate codes
has not been answered for more than a decade. We present a generalization of
the quantum Hamming bound, which was originally formulated for the case of
noise acting independently on the encoding systems, to a generic noise
process. We show in particular that in the presence of correlated noise the
bound is violated by employing degenerate codes. 
Nakahara, Mikio:
Neutral Atom Quantum Computer with OnDemand Interaction
We
discuss an implementation of a neutral atom quantum computer, where atoms
are trapped in an array of nearfield Fresnel light. The trap light is
supplied through an optical fiber attached to each trap. Singlequbit gate
operation is realized by the twophoton Raman transition, which is
controlled by another laser beam through the same fiber. Selective 2qubit
gate operation is implemented by leaving two atoms in a 1dimensional
optical lattice and then colliding a particular set of quantum states of
these atoms to obtain an extra phase. We believe the proposed scheme is
realizable within current technology. 
Pascazio, Saverio: Multipartite entanglement
and frustration
Entanglement is one of the most intriguing features of quantum mechanics. It
is widely used in quantum communication and information processing and plays
a key role in quantum computation. At the same time, entanglement is not
fully understood. It is deeply rooted into the linearity of quantum theory
and in the superposition principle and (for pure states) it is essentially
related to the impossibility of factorizing the state of the total system in
terms of states of its constituents. The characterization and quantification
of entanglement is an open and challenging problem. One can give a good
definition of bipartite entanglement in terms of the von Neumann entropy or
the entanglement of formation. The problem of defining multipartite
entanglement is more difficult and no unique definition exists. We introduce
the notion of maximally multipartite entangled states (MMES) of n qubits as
a generalization of the bipartite case. The bipartite entanglement of a MMES
is almost independent of the bipartition and is maximal for all possible
bipartitions. Some examples of MMES for few qubits are investigated. For a
larger number of qubits the search for MMES becomes more involved and
unearths the presence of frustration. MMEs are the solution of an
optimization problem that can be recast in terms of classical statistical
mechanics. We focus on fundamental issues and possible applications (quantum
teamwork). 
Abstractinvited talks: 
AbdelAty, Mahmoud:
Longlived geometric phase of superconducting qubits with nanomechanical
resonators
We
propose a scheme for environmentinduced a longlived geometric phase using
supercoducting artificial atoms. The system is analogous to a collection of
artificial fewlevel atoms (the Josephson junctions) coupled to the
resonators. In this scheme, the nanomechanical resonator plays an important
role to contribute additional auxiliary energy levels to the artificial
atoms. Increasing the number of atoms as revealed in a high degree of
extinction of propagating waves, plays the opposite role of the environment
effect. It is shown that the environment provides a mechanism for the
generation of geometric phases. 
Akhtarshenas, Seyed Javad: Concurrence of
Superpositions
Recently, Linden, Popescu and Smolin [Phys. Rev. Lett., 97, 100502
(2006)] have raised the following problem: Given a bipartite quantum state
and a certain decomposition of it as a superposition of two others, what is
the relation between the entanglement of the state and those of the two
states in the superposition? In this paper we use the concurrence vector as
a measure of entanglement and investigate upper and lower bounds on the
concurrence of the state as a function of the concurrence of the superposed
states. We show that the concurrence vector enables us to extend the results
to the superpositions of two multipartite states. 
Barrett, Sean: Fault tolerant quantum
computation with very high threshold for loss errors
Many
proposals for fault tolerant quantum computation (FTQC) suffer detectable
loss processes. Here we show that topological FTQC schemes, which are known
to have high error thresholds, are also extremely robust against losses. We
demonstrate that these schemes tolerate loss rates up to 24.9%, determined
by bond percolation on a cubic lattice. Our numerical results show that
these schemes retain good performance when loss and computational errors are
simultaneously present. This talk is based on the preprint arXiv:1005.2456. 
Browne, Dan:
Linearity and loopholes: On Bell inequalities and measurementbased
quantum computation
We
show [1] that multiparty generalisations of the CHSH inequality can be
elegantly derived in a framework similar to measurementbased quantum
computation. This gives an operational meaning of what it means to violate a
CHSHtype inequality, which allows us to characterise the effect of
"loopholes" in Bell inequality experiments. We show that adaptive
measurements of the kind which occur in measurementbased quantum
computation may be simulated without introducing a loophole, and that this
means that one can contrast local hidden variable correlations with a wider
class of quantum correlations than traditionally considered.
[1] M.
Hoban and D.E. Browne, in preparation 
de Guise, Hubert: Dynamical symmetry reduction
and tomography of threelevel atoms
I will
discuss how the level structure of threelevel atoms may the possible
tomographic reconstructions of a system of threelevel atoms. The
particular case of the ∑ atom will be discussed in greater length with
emphasis on the problem of selecting a finite set of transformations that
will optimize the reconstruction.(work done in collaboration with Andrei
Klimov and Dylan Mahler) 
de
Oliveira, Marcos: Entanglement, quantum
discord, and the power of the quantum computer
Universidade Estadual de Campinas, Brazil
We
present a direct and general relation between entanglement of formation and
quantum discord. By extending the relation to a paradigmatic situation of a
bipartite system coupled to the environment we show that in the
deterministic quantum computer with one pure qubit (DQC1) the protocol has
the ability to rearrange the entanglement and the quantum discord, which are
present and distributed following a monogamic relation. This implies that
quantum computation can be understood in a different ground as a coherent
dynamics where quantum correlations are distributed between the qubits of
the computer. In addition, we extend the discussion for an arbitrary
tripartite mixed system, showing the existence of an inequality for the
subsystems entropies with stronger bounds than the usual strong
subadditivity. 
Kamli, Ali: Nonlinear optics with surface
polaritons
We
discuss basic properties of surface polaritons (SP) qubits, namely
confinement and losses in the presence of a meta material interface. Using
electromagnetically induced transparency technique we show that SPs modes
can be controlled, manipulated and slowed down to very low velocities. This
enables information encoded in SP qubits to be stored and retrieved
according to EIT protocol. Furthermore employing double EIT mechanism we
demonstrate that the interaction of two SP qubits can generate large Kerr
nonlinearity with phase shift of order π which is essential for application
in quantum phase gates a necessary ingredient in quantum computing.
References:
A. A. Kamli, S. A. Moiseev and B. C. Sanders; Phys. Rev. Lett. 101,
263601 (2008).
S. A. Moiseev, A. A. Kamli and B. C. Sanders; Phys. Rev. A 81, 033839
(2010). 
Langari, Abdollah:
Renormalization of concurrence: Quantum information properties close to
quantum critical point via the renormalization group
My
presentation is a collection of our recent investigations on the quantum
information properties of spin models close to the quantum critical points.
I first introduce the implementation of quantum renormalization group to get
the quantum critical properties of a spin model. This implementation is used
to show the evolution and finite size scaling of entanglement and its
derivative close to quantum critical point of the Ising model in transverse
magnetic field (ITF). The finite size analysis of the entanglement
derivative is presented. We have found that the derivative of concurrence
between two blocks each containing half of the system size diverges at the
critical point with the exponent, which is directly associated with the
divergence of the correlation length. From the same point of view the
quantum phase transition of XXZ model from the Neel phase to the spin liquid
one is presented. The nonanalytic behavior comes from the divergence of the
first derivative of both measures of entanglement as the size of the system
becomes large. The renormalization scheme demonstrates how the minimum value
of the first derivative and its position scales with an exponent of the
system size. We have also investigated the effect of DzyaloshinskiiMoriya
interaction on the quantum information properties of ITF and XXZ model close
to their quantum critical boundaries. Finally, the most recent results are
presented on the connection between quantum information property and quantum
critical point of the Kondonecklace model which is obtained by the
continuous unitary transformations. 
Stace, Tom: Quantum error correction thresholds
in the presence of loss
Toric codes are very powerful error correcting codes, which achieve very
high error correction thresholds. In this talk, I will introduce toric
codes as quantum memories, explain how they work, and demonstrate their
tolerance against errors. I will then discuss some recent results that show
they are also extremely robust against losses. 
Abstractcontributed talks: 
Arshed,
Nigum: Channel Capacities of an Exactly Solvable
SpinStar System
We
calculate the entanglementassisted and unassisted channel capacities of an
exactly solvable spin star system, which models the quantum dephasing
channel. The capacities for this nonMarkovian model exhibit a strong
dependence on the coupling strengths of the bath spins with the system, the
bath temperature, and the number of bath spins. For equal couplings and bath
frequencies, the channel becomes periodically noiseless. 
Bayat,
Abolfazl: Entanglement Routers Using Macroscopic
Singlets
University College London, UK
We
propose a mechanism where high entanglement between very distant boundary
spins is generated by suddenly connecting two long Kondo spin chains. We
show that this procedure provides an efficient way to route entanglement
between multiple distant sites which is useful for quantum computation and
multiparty quantum communication. We observe that the key features of the
entanglement dynamics of the composite spin chain are remarkably well
described using a simple model of two singlets, each formed by two spins.
The proposed entanglement routing mechanism is a footprint of the emergence
of a Kondo cloud in a Kondo system and can be engineered and observed in
varied physical settings. 
Burgarth, Daniel: Indirect Quantum Tomography of
Quadratic Hamiltonians
Imperial College London, UK
A
number of manybody problems can be formulated using Hamiltonians that are
quadratic in the creation and annihilation operators. Here, we show how such
quadratic Hamiltonians can be efficiently estimated indirectly, employing
very few resources. We find that almost all properties of the Hamiltonian
are determined by its surface, and that these properties can be measured
even if the system can only be initialized to a mixed state. Therefore our
method can be applied to various physical models, with important examples
including coupled nanomechanical oscillators, hopping fermions in optical
lattices, and transverse Ising chains. 
Ciccarello, Francesco: Optimal and scalable
telecloning in a limitedcontrol scenario
University of Palermo, Italy
Quantum telecloning [1] is a Quantum Information Processing task, which
allows to achieve optimal spreading among N receivers of the quantum
information initially possessed by one sender. So far, to the best of our
knowledge, no scheme for the actual implementation of such a process in a
scalable way has been proposed. Here, we first show the existence of a class
of manyqubit singlets allowing for optimal and scalable telecloning. Next,
we illustrate a protocol to prepare such states in a setting where
scattering centers possessing a spin degree of freedom interact by means of
mobile particles. The scheme is understood simply by resorting to an
appropriate coupling scheme for the addition of angular momenta and
Hamiltonian symmetries. Major practical advantages of our scheme lie on the
management of stationary and well separated spins along with the mild
requirement to perform simple Geiger measurements over the mobile particles
to establish the necessary multipartite entanglement [3, 4]. We also show
strategies that allow generating in the same setting other important manyqubit
states such as Aharonov, W and GHZ states.
[1] M.
Murao, D. Jonathan, M. B. Plenio, and V. Vedral, Phys. Rev. A 59, 156
(1999).
[2] F. Ciccarello, M. Paternostro, S. Bose, D. Browne, G. M. Palma and M.
Zarcone, arXiv:1003.2171 (2010).
[3] F. Ciccarello, M. Paternostro, G. M. Palma and M. Zarcone, New J. Phys.
11, 113053 (2009).
[4] F. Ciccarello, S. Bose and M. Zarcone, Phys. Rev. A 81, 042318
(2010). 
Fei,
ShaoMing: Quantum Entanglement and Experimental
Determination
Capital Normal University, China
We
discuss quantum entanglement and its experimental determination. In
particular the way of experimentally determining the concurrence in terms of
the expectation values of local observable, the criteria related to Bell
inequalities which are sufficient and necessary for the separability of
general pure multipartite quantum states in arbitrary dimensions, as well as
the relation between violation of Bell inequalities and distillability
properties of quantum states will be investigated. 
Khan,
Faisal: A Game Theoretic Approach to Quantum Markov
Processes
Khalifa University of Science, Technology & Research, UAE
In the
context of quantum information theory, "quantization" of various
mathematical and computational constructions is said to occur upon the
replacement, at various points in the construction, of the classical
randomization notion of probability distribution with higher order
randomization notions from quantum mechanics such as quantum superposition
with measurement. For this to be done "properly", a faithful copy of the
original construction is required to exist within the new "quantum" one,
just as is required when a function is extended to a larger domain. Here
procedures for extending history dependent Parrondo games, Markov processes
and multiplexing circuits to their "quantum" versions are analyzed from a
game theoretic viewpoint, and from this viewpoint, proper quantizations
developed. 
Kondo,
Yasushi: Composite Quantum Gates with Vanishing
Dynamic Phases
Kinki
University, Japan
We
show that all composite quantum gates with vanishing dynamic phases are
robust against control field strength errors. As examples of this
observation, we show (1) how a robust composite rfpulse in NMR is
geometrically constructed and (2) a composite rfpulse based on
TrotterSuzuki Formulas is a geometric quantum gate. 
Majumdar, Archan S.: Information processing by
single particle hybrid entangled states
Salt
Lake, Kolkata, India
We
first discuss schemes for generating entanglement between different degrees
of freedom of the same particle. Using single particle entangled states as
resources we formulate protocols for entanglement swapping and teleportation
of usual qubit states. We also present proposals for testing quantum
contextuality and nolocality of single particle states generated through
atomphoton interactions in cavity quantum electrodynamics. 
Marzolino, Ugo: Subshotnoise quantum metrology
with entangled identical particles
University of Trieste, Italy
The
usual notion of separability has to be reconsidered when applied to states
describing identical particles. A definition of separability not related to
any a priori Hilbert space tensor product structure is needed: this can be
given in terms of commuting subalgebras of observables. Accordingly, the
results concerning the use of the quantum Fisher information in quantum
metrology are generalized and physically reinterpreted. 
SaiToh,
Akira: Practical evaluation of an MPS simulation as
a classical search tool
Kinki
University, Japan
We
present our recent results of the studies to evaluate a matrixproductstate
(MPS) simulation of a bulkensemble search as a classical search tool. The
dominant computational cost is the cost to simulate an oracle circuit
because the number of queries is not dominant: it is linear in the input
size and the number of solutions. The rounding error is avoided by using a
multiprecision programming library. The total cost is well characterized by
the cube of the maximum Schmidt rank during the simulation. It is known that
the upper bound of the maximum Schmidt rank increases exponentially in the
depth of mutually overlapping gates in the quantum circuit in MPS
simulations in general. We show that the increase is considerably small in
practical Oracle circuits for classical satisfiability problems and the
variants. Even in hard instances for classical random searches, namely
instances with a small number of truth assignments, the increase is shown to
be slow in the circuit depth, so far as we could test. In contrast, there
are some hard instances for the MPS method, namely those results in a large
Schmidt rank that are easy instances for classical random searches. 
Shadman, Zahra: Nonunitary encoding increases the
super dense coding capacity in the presence of noise
Dusseldorf
University, Germany
We
study an important protocol in quantum information processing, namely super
dense coding in the presence of noise. We compare the optimal super dense
coding capacity with unitary and nonunitary encoding. We show that in the
case of nonunitary encoding, the optimal capacity can be reached by
preprocessing on the sender's
side followed by a unitary encoding. We give examples that preprocessing
increases the super dense coding capacity.

Abstractposters: 
01.
Abdullah, Shirwan: Entanglement Indicators in Quantum Dots
University of York, UK
We
calculate spatial entanglement between two electrons trapped in quantum dots
for abroad class of confinement potentials with different type and geometry,
we make comparison between entanglement content of the system for different
cases. The manybody wave function has been calculated by
exact
diagonalization of the time independent Schrodinger equation. We show that
some physical property of the system could by a good entanglement indicator.
Entanglement has an inverse correlation with Coulomb interaction energy in
some cases, so it can be used as an entanglement indicator. We show that the
wave function at a single highly symmetric point is also a good entanglement
indicator. We investigate the possibility of finding a general indicator
that will be common for all cases. We study the effect of internal
nanostructure parameters and the external fields on entanglement property in
systems with different confinement potential type and geometry. This
property may be used to tailor nanostructures according to the level of
entanglement required by a specific application. 
02.
Ahmadi, Fatemeh: Fidelity for States of Two Spin1/2 Particles in Moving
Frames
Amirkabir University, Iran
Fidelity for the spin part of states of two spin1/2 particles is
investigated from the view point of moving observers. Using a numerical
approach, the behavior of the fidelity in terms of the boost parameter is
described for different amounts of spin entanglement and momentum
entanglement. It is shown that for the spin entangled states the fidelity
decreases less than that of the case of spin product states and there are
special cases for which the fidelity remains perfect regardless of moving
observers
velocity. Generally, in the limit of boosts with speeds close to the speed
of light, the fidelity saturates, i.e., it reaches to a constant value that
depends on the amount of momentum entanglement and the width of the momentum
distribution function.

03.
Akhound , Ahmad: Multiqubit entanglement and the critical entangling
field
Payame
Noor University, Iran
We
consider an initial multiqubit coherent state and study its evolution by
the twoaxis counter twisting Hamiltonian and investigate its entanglement
properties via concurrence in the presence and absence of an external
magnetic field. It is observed that in the absence of the external field,
the system is not entangled in some time intervals. If the field is
increased up to the critical value, the nonexistence periods vanish and
barring some separate instances of time, the system becomes continuously
entangled. We also define the optimal field at which the time average value
of the concurrence assumes the highest possible value [1]. We observe that
the fluctuations decrease if the external field is increased, but a tradeoff
is involved; the value of the average concurrence is reduced. We plot
concurrence versus the external field for several spins and field values.
[1] M.
Jafarpour and A. Akhound, Entanglement and squeezing of multiqubit
systems using a twoaxis countertwisting Hamiltonian with an external field,
Phys. Lett. A 372, (2008).
[2] X. Wang and K. Molmer,
Pairwise entanglement in symmetric multiqubit systems, Eur. Phys. J.
D 18 (2002). 
04.
Alipour, Sahar: Markovianity of quantum channels and quantum estimation
Sharif
University of Technology, Iran
We
investigate how Markovianity of a quantum dynamics may affect accuracy of
the estimation of dynamical parameters. For quantum Markovian dynamics, the
time derivative of quantum Fisher information (QFI) is shown to be negative.
When symmetric logarithmic derivative (SLD) is taken with respect to a
parameter of initial state, this negativity demonstrates loss of
distinguishability with time. However, when SLD is taken with respect to a
dynamical parameter, the negativity of the rate of QFI shows that the state
eventually approaches a stationary fixed state. As a result, in this case
the estimation of channel parameters becomes difficult with time. [Joint
work with A.T. Rezakhani] 
05.
Annabestani, Mostafa: Shifting position decoherence in onedimensional
discrete time quantum walk
Tarbiat Modares University, Iran
We
have investigated the shifting position decoherence in onedimensional
discrete time quantum walk (DTQW) which arise from the tunneling effect in
the experimental realization of quantum walk. We proved that the quantum
behavior of 1DQW in the presence of tunneling effect doesn't fade, unlike
the case in which coin subspace is subject to decoherence where in this
case, system transition to classic even for weak strength of noise. We show
that quadratic dependency of variance on time, which is pure quantum
property of coherent QW, remain quadratic in the presence of tunneling
decoherence and coinposition entanglement (CPE), which is another pure
quantum property and converge to significant value for any strength of
noise. Furthermore we show that this type of decoherence smooth the
probability distribution and we represent the compact formula for
probability distribution in terms of coherent onedimensional quantum walk
(1DQW). 
06.
Baghbanzadeh, Sima:
Bound
entanglement in quantum phase transitions
Sharif
University of Technology, Iran
Entanglement as a crucial ingredient of quantum manybody systems has
different forms, such as free entanglement and bound entanglement. In this
study we show that, like free entanglement, bound entanglement can also
induce quantum phase transitions. We investigate quantum phase transitions
in which a change in the type of entanglement from bound entanglement to
either free entanglement or separability may occur. In particular, we
present a theoretical method to construct a class of quantum spinchain
Hamiltonians that exhibit this type of quantum criticality. Given
parameterdependent twosite reduced density matrices (with prescribed
entanglement properties); we lay out a reverse construction for a compatible
pure state for the whole system, as well as a class of Hamiltonians for
which this pure state is a ground state. This construction is illustrated
through several examples. 
07.
Barzanjeh, Shabir: Dynamical behavior of entanglement in semiconductor
microcavities
University of Isfahan, Iran
We
investigate evolution of entanglement in a semiconductor cavity QED
containing a quantum well. By using Wehrl entropy and introducing
generalized concurrence as entanglement measures, we show the influence of
the system parameters on the evolution features of entanglement. 
08.
Eslami, Leila: Double quantum ring with Rashba spinorbit interaction as
a quantum NOT gate
Iran
University of Science and Technology, Iran
During
the last years, many studies have been done on mesoscopic quantum rings made
of semiconductors like InGaAs because of their ability to show quantum
interference effects such as AharonovBohm oscillations and spin dependent
quantum transport (spintronics). The study of electronics and spintronics in
mesoscopic systems can be used to improve designing and manufacturing of
quantum computing devices. Manipulating spin degree of freedom is one of
important fundamental subjects in quantum computing field. One of mechanisms
which can control spin transport of electron is Rashba spinorbit
interaction. In previous works spinpolarized persistent current,
spinfiltered electron transmission to single quantum ring and also spin
separation via a three terminal quantum ring have been proposed using Rashba
spinorbit interaction. In this study we introduce double quantum rings
connected each other by a normal lead with perpendicular electric field
implied on each of them. Electron beam injected from an incoming lead which
is connected to the first quantum ring and transmitted to an outgoing lead
connected to the second quantum ring. We use Smatrix formalism to study
spin dependent transport of electron through this system. We find that by
adjusting parameters of the system (such as the Rashba spinorbit
interaction, geometry of connected rings, strength of coupling constant of
leads to the rings and energy of the incident electron beam) properly the
system can act as a quantum NOT gate which flips the spin of injected
electron from up to down and vice versa. 
09.
Fasihi Aghbolagh, Mohammad A.: Entanglement of Fermionic Coherent States
for Pseudo Hermitian Hamiltonian
Kinki
University, Japan
In
this paper the entanglement of multiqubit fermionic pseudo Hermitian
coherent states (FPHCS) described by anticommutative Grassmann numbers is
studied. The pseudoHermitian versions of the wellknown maximally entangled
pure states such as GHZ, W, Bell and biseparable states are introduced
through integrating over tensor product of FPHCSs with suitable choice of
Grassmannian weight function. Meanwhile to clarify the issue, as an example,
a two level pseudo Hermitian Hamiltonian is introduced and using its
biorthogonal eigenvectors we construct all possible pseudo Hermitian
versions of Bell, W and GHZ states as a tensor product of them. Then using
the concurrence measure for two qubit states, entanglement of these states
is calculated as a function of the parameters of the pseudo Hermitian
Hamiltonian and it is shown that in some special points, the amount of their
entanglement coincide with maximal value. Using average entropy the same
results are deduced for pseudo W and GHZ states constructed by biorthogonal
eigenvectors of pseudo Hermitian Hamiltonian and it is shown that, as a
limit point, the maximal values are achieved for Hermitian one. 
10. Gutschow,
Johannes: Performance of quantum convolutional coding with memory
constraints
Universitat
Hannover, Germany
Quantum convolutional errorcorrecting codes [1] are often said to
outperform block codes in terms of code rate and decoding complexity.
However, there is no general proof of this. For example many promising
examples of convolutional codes turn out to have bad properties, such as
being
catastrophic
and thus spreading errors infinitely. The question we address here is the
memory requirements of the encoding and decoding procedures for quantum
convolutional codes. We introduce a description of convolutional stabilizer
codes (CSC) by Clifford channels with memory that enables us to relate
properties of the encoders to simple conditions on the classical
representation of the channel. For example, the encoder of a CSC is
noncatastrophic, if and only if the channel describing it is strictly
forgetful, i.e., the influence of the original memory input vanishes after
finitely many uses of the channel. This is in turn true, if and only if the
memorytomemory reduction of the channel is a nilpotent matrix. Using this
description, we present a Hamming bound for convolutional stabilizer codes
and discuss it with respect to coding under memory constraints. We show
that convolutional codes are especially suitable in asymmetric setups,
because, to use the power of the convolutional scheme, the decoder requires
more memory than the encoder. Finally we illustrate our findings with
examples of convolutional stabilizer codes.
[1]
Harold Ollivier and JeanPierre Tillich. Quantum
convolutional codes: fundamentals. preprint, Jan 2004; arXiv:quantph/0401134 
11. Haibati, Ozra: Measuring Entanglement between Two Cavities Quantum
Electrodynamics
Zanjan
University, Iran
We
propose a new experimental setup of the MachZendher interferometer for the
three levels Rydberg atoms. The three levels Rydberg atomic systems are
interacted with two entangled cavities quantum electrodynamics. In our
proposal the state of incoming atoms and entangled cavities (C_{1}
and C_{2}) are denoted by g> and a 0, 1> +
b 1, 0>, respectively. The amount of entanglement is measured by the
imaginary parameters a, b. We have a=b=1/√2 for
maximum entanglement, a = 1, b = 0 (or a = 0, b
= 1) for no entanglement and otherwise partially entanglement states. One of
the cavities is placed in clockwise path of interferometer and the other one
is placed in counterclockwise path. In each path two cavities are
sandwiching C_{i} (i = 1, 2) that R_{i}
(i = 1, 2 or i = 3, 4) are identical low Q cavities. In
this case, the Rydberg atoms interact classically with the resonance
cavities R_{i} and quantum mechanically with the out of
resonance cavities C_{i}. For a specific phase difference in
R_{i} cavities, the entangled parameters are involved in the
outgoing state of atom. It is shown that the measurement of the state of
individual outgoing atoms give us the entanglement parameters a, b as
well as the phase difference between two paths. Furthermore, the result is
given in terms of the value of the Wigner function at the origin. 
12.
Herrera Marti, David: A photonic Implementation of the Topological
Cluster State Computer
Imperial College London, UK
A new
experimental implementation of the topological cluster state quantum
computer is suggested, in which the basic elements are linear optics,
measurements, and a twodimensional array of light strobed quantum dots.
This overcomes the need of nonlinear devices to create a lattice of
entangled photons. 
13.
Heshami, Khabat: Quantum memory based on controllable transition dipole
moment
University of Calgary, Canada
To
build quantum memory for light with atomic ensembles one need to map single
photons into atomic excitations and freeze them until releasing them back to
photons on demand. Here we present an idea for realizing this storagerecall
procedure by directly turning transition dipole moment on and off in a
twolevel system. An analytical treatment of the problem is performed and
the physical requirements on the proposed scheme are discussed. Employing a
magnetodependent transition dipole moment in Tm3+: YAG crystal, we show a
good instructive quantum memory using this simple idea. 
14.
Houshmand, Monireh: Minimal memory requirements for pearl necklace
encoders of quantum convolutional codes
Ferdowsi University of Mashhad, Iran
One of
the major goals in quantum computer science is to reduce the overhead
associated with the implementation of quantum computers, and inevitably,
routines for quantum error correction will account for most of this
overhead. A particular technique for quantum error correction that may be
useful in the outer layers of a concatenated scheme for fault tolerance is
quantum convolutional coding. The encoder for a quantum convolutional code
has a representation as a convolutional encoder or as a pearl necklace
encoder. In the pearl necklace representation, it has not been particularly
clear in the research literature how much quantum memory such an encoder
would require for implementation. Here, we offer an algorithm that answers
this question. The algorithm first constructs a weighted, directed acyclic
graph where each vertex of the graph corresponds to a gate string in the
pearl necklace encoder, and each path through the graph represents a
noncommutative path through gates in the encoder. We show that the longest
path through the graph corresponds to the minimal amount of memory needed to
implement the encoder. A dynamic programming search through this graph
determines the longest path. The running time for the construction of the
graph and search through it is quadratic in the number of gate strings in
the pearl necklace encoder. 
15.
Jafarpour, Mojtaba: Optimal and critical squeezing fields for a multiqubit
spin system
Shahid
Chamran University, Iran
We
consider a multiqubit spin system initially in a coherent state, whose
internal interactions are described by a oneaxis twisting Hamiltonian [1,
2]. We study its squeezing dynamics and calculate its squeezing parameter in
the presence and absence of an external magnetic field. A critical magnetic
field is introduced for this system; if the external field is increased up
to, the system becomes continuously squeezed. We also introduce an optimal
field, at which the average depth of the squeezing parameter is maximized.
We may increase the external field to the values higher than to decrease the
squeezing fluctuations, but a tradeoff is involved; the squeezing depth is
decreased as a result.
[1] M.
Kitagawa and M. Ueda, Squeezed spin states, Phys. Rev. A 47,
51385143 (1993).
[2] A. Akhound and M. Jafarpour, Spin squeezing Hamiltonian and optimal
spin squeezing parameters, IL NuovoCimento B 122 (6), 885896, Doi
10.1393/ncb/i2007103982 (2007). 
16.
Lupo, Cosmo: Memory effects in attenuation and amplification quantum
processes
University of Camerino, Italy
With
increasing communication rates via quantum channels, memory effects become
unavoidable whenever the use rate of the channel is comparable with the
typical relaxation time of the channel environment. We then introduce a
model of bosonic memory channel, describing correlated noise effects in
quantum optical processes via attenuating or amplifying media. To study such
a channel model we make use of a proper set of collective field variables,
which allows us to unravel the memory effects, mapping the nfold
concatenation of the memory channel to a, unitarily equivalent, direct
product of n singlemode bosonic channels. We hence estimate the
channel capacities by relying on known results for the memoryless setting.
Our findings show that the model is characterized by two different regimes,
in which the crosscorrelations induced by the noise among different channel
uses are either exponentially enhanced or exponentially reduced. 
17.
Mahdian, Mohammad: Quantifying spinmomentum correlation in
singleparticle quantum states using nonlinear entanglement witnesses
University of Tabriz, Iran
We
present a unifying approach to the quantification of spinmomentum
correlation of single spin half and one particle by using the NonLinear
entanglement witnesses (NLEWs) which have been constructed based on convex
optimization method. Likewise, we show that for quantum mixed states which
are made by means of two types of degrees of freedom spin and momentum, the
effect of the Lorentz transformation is to decrease both the amount and the
region of entanglement. 
18.
Maleki, Yusef: Entanglement of Grassmannian Coherent States
Mohaghegh Ardabili University, Iran
In
this paper we investigate the entanglement of multipartite Grassmannian
coherent states (GCS) described by Grassmann numbers. Choosing an
appropriate weight function, we show that it is possible to construct some
entangled pure states, consisting of GHZ, W, Bell, cluster
type and biseparable states, by tensor product of GCSs. It is shown that for
three level systems, the Grassmann creation and annihilation operators b
and b^{ }
together with b_{z} form a closed deformed algebra SU_{q}
(2) with q = e^{2 π i / 3 }which is useful to construct
entangled qutritstates. The same argument hold for three level squeezed
states. Moreover combining the Grassmann and bosonic coherent states we
construct maximal entangled supersymmetric coherent states. Finally a
comparison with maximal entangled bosonic coherent states is presented and
it is shown that in some cases they have fermionic counterpart which are
maximal entangled after integration with suitable weight functions. 
19.
Mani, Azam: TimeDependent Memory Channel
Sharif
University of Technology, Iran
We
present a model for memory channels which is more realistic than the studied
ones. In this model, the quantum system of our interest is coupled to a
classical environment so that the state of both system and environment
changes with time. During the relaxation process of environment, two qubits
interact with it at different times and thus are affected by different
channels. In other words, we have time dependent memory channel which
relaxes to a specific channel. We consider the role of time interval between
sending the qubits in the relaxation time of environment and thus behavior
of the resulting channel. 
20.
Marvian Mashhad, Milad: Generalizing Quantum Secret Sharing Using Secure
Carriers
Sharif
University of Technology, Iran
We
generalize the secret sharing scheme of reference [1] to more general access
structures, namely a large class of (k, n) threshold schemes.
The basic property of our scheme and that of [1] is that the entanglement is
not used as a resource, but can be regenerated after each round of the
protocol by suitable unitary operations of all the dealers. In effect an
entangled state shared between all the participants plays the role of a
carrier to which information is hooked by the sender and unhooked by the
legitimate parties, by suitable operations. In view of the high cost of
entanglement generation, our scheme may find useful applications in the
future.
[1]
Saber Bagherinezhad, Vahid Karimipour, Quantum secret sharing based on
reusable GHZ states as secure carriers Physical Rev. A 67, 044302
(2003). 
21.
MehriDehnavi, Hossein: Entanglement of pseudopure spinor state in
accelerated frames
Kinki
University, Japan
We
study the entanglement of a class of pseudopure stats in noninertial
frames. We will show that logarithmic negativity decrease with respect to
acceleration and we can show that there are some initially entangled states
can be observed as separable states in noninertial frames with finite
acceleration. Also, it can be shown that the mutual information tends to
half of its initial value in the limit of infinite acceleration. 
22.
Memarzadeh Esfahani, Laleh: Quantum information reclaiming by classical
feedback from the environment
University of Camerino, Italy
We
investigate the quantum information reclaim from the environment after
amplitude damping has occurred. In particular we address the question of
optimal measurement on the environment to perform the best possible
correction on two and three dimensional quantum systems. Depending on the
dimension we show that the entanglement fidelity (the measure quantifying
the correction performance) is or is not the same for all possible
measurements and uncover the optimal measurement leading to the maximum
entanglement fidelity. Furthermore, we study random unitary channel acting
on nqubits by using the classical result of measurement on the
environment of m. 
23.
Mohammady, Mohammad H.: Bismuth in silicon qubits: the role of EPR
cancellation resonances
University College London, UK
We
investigate theoretically and experimentally the electron paramagnetic
resonance (EPR) spectra of bismuth doped silicon (Si:Bi) at intermediate
magnetic fields, B ≈ 0.050.6 T. We identify a previously unexplored EPR
regime of "cancellationresonances" where part of the hyperfine coupling is
resonant with the external fieldinduced splitting. We show this regime has
interesting and experimentally accessible consequences for spectroscopy and
quantum information applications. These include reduction of decoherence,
fast manipulation of the coupled nuclearelectron qubit system and line
narrowing in the multiqubit case. We test our theoretical analysis by
comparing with experimental Xband (9.7 GHz) EPR spectra obtained in the
intermediate field regime. 
24.
Moradi, Shahpoor: Two accelerated observers and degradation of
entanglement
Razi
University, Iran
We
study the entanglement of free scalar and Dirac fields as seen by two
accelerated parties. We also study the entanglement distillability of
bipartite mixed states of two modes of a free Dirac field, seen by two
accelerated parties in the context of Werner states. We conclude that if we
considered two accelerated observers instead one, the density matrix would
be mixed to a higher degree, resulting in a higher degradation of
entanglement. 
25.
Najarbashi, Ghader: Maximal Entanglement of Twoqubit States Constructed
by Linearly Independent
University of Mohaghegh Ardabili, Iran
In
this work, we find the necessary and sufficient condition for the maximal
entanglement of the state, ψ> = μα>β> + λα>δ>
+ ρϒ>β>
+ νϒ>δ>,
constructed by linearly independent coherent states with real parameters
when <αϒ>=<βδ>.
To this aim we use the concurrence. 
26.
Rezaei Karamati, Mahdi: Molecular solution for the subsetsum problem on
DNA
based
quantum computing
University of Tabriz, Iran
Feynman in 1961 and in 1982 respectively proposed molecular computation and
one of the most important problems in computation theory, that is, whether
computing devices based on quantum theory are able to finish computations
faster than the standard Turing machines. In 1994, Adleman succeeded to
solve an instance of the Hamiltonian path problem in a test tube, just by
handling DNA strands. Deutsch denoted a general model of quantum computation
 the quantum Turing machine. Molecular solution for the subsetsum problem
on DNA based supercomputing has been offered in Wenglong Chang et al.
2003 articles. Here, it is demonstrated that the DNAbased algorithm of an
nbit parallel adder and a DNA based algorithm of an nbit parallel
comparator to formally verify our designed molecular solutions for the
subsetsum problem can
be implemented by Hadamard gates, NOT gates, CNOT gates, CCNOT gates, Grovers
operators,
and quantum measurements on a quantum computer. 
27.
Sadeghi, Parvin: Tesallis entropy in the Husimi and Wigner
representations
Zanjan
University, Iran
In
this paper the Tesallis entropy is developed into the phase space picture of
quantum mechanics, for an ordinary range of qparameters. We apply
the Tesallis entropy for the Schrodinger Cat State (SCS) in the Husimi and
Wigner representations. It will reduce to the Whrel and linear entropies for
a corresponding qparameter. The variations of the Tesallis entropy
in terms of the nonlinear effect and strong field for the SCS are compared
with the corresponding SCS quantum signature which is introduced by Kenfack
et al. We find a suitable qparameter for the Tesallis entropy
which has a best fitting with the quantum signature.



