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The Ryu-Takayanagi (RT) formula relates the entanglement entropy of a region

in a holographic theory to the area of a corresponding bulk minimal surface.

Using the max flow-min cut principle, a theorem from network theory, we rewrite

the RT formula in a way that does not make reference to the minimal surface.

Instead, we invoke the notion of a "flow", defined as a divergenceless

norm-bounded vector field, or equivalently a set of Planck-thickness "bit

- Read more about Bit threads and holographic entanglement. (arXiv:1604.00354v3 [hep-th] UPDATED)
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We investigate the effect of spatial disorder on the edge states localized at

the interface between two topologically different regions. Rotation disorder

can localize the quantum walk if it is strong enough to change the topology,

otherwise the edge state is protected. Nonlinear spatial disorder, dependent on

the walker's state, attracts the walk to the interface even for very large

coupling, preserving the ballistic transport characteristic of the clean

regime.

Simulating quantum nonlocality and steering requires augmenting pre-shared

randomness with non-vanishing communication cost. This prompts the question of

how one may provide such an operational characterization for the quantumness of

correlations due even to unentangled states. Here we show that for a certain

class of states, such quantumness can be pointed out by superlocality, the

requirement for a larger dimension of the pre-shared randomness to simulate the

- Read more about Nonclassicality of local bipartite correlations. (arXiv:1609.08090v3 [quant-ph] UPDATED)
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For any given channel $W$ with classical inputs and possibly quantum outputs,

a dual classical-input channel $W^\perp$ can be defined by embedding the

original into a channel $\mathcal N$ with quantum inputs and outputs. Here we

give new uncertainty relations for a general class of entropies that lead to

very close relationships between the original channel and its dual. Moreover,

we show that channel duality can be combined with duality of linear codes,

- Read more about Duality of channels and codes. (arXiv:1701.05583v1 [quant-ph])
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We study characteristics of quantum evolution which can be called curvature

and torsion. The curvature shows a deviation of the state vector in quantum

evolution from the geodesic line. The torsion shows a deviation of state vector

from the plane of evolution (a two-dimensional subspace) at a given time.

We illustrate the adiabatic quantum computing solution of the knapsack

problem with both integer profits and weights. For problems with $n$ objects

(or items) and integer capacity $c$, we give specific examples using both an

Ising class problem Hamiltonian requiring $n+c$ qubits and a much more

efficient one using $n+[\log_2 c]+1$ qubits. The discussion includes a brief

mention of classical algorithms for knapsack, applications of this commonly

occurring problem, and the relevance of further studies both theoretically and

One of the main interest in quantum cosmology is to determine boundary

conditions for the wave function of the universe which can predict

observational data of our universe. For this purpose, we solve the

Wheeler-DeWitt equation for a closed universe with a scalar field numerically

and evaluate probabilities for boundary conditions of the wave function of the

universe. To impose boundary conditions of the wave function, we use exact

solutions of the Wheeler-DeWitt equation with a constant scalar field

The aim of this paper is to bring together the notions of quantum game and

game isomorphism. The work is intended as an attempt to introduce a new

criterion for quantum game schemes. The generally accepted requirement forces a

quantum scheme to generate the classical game in a particular case. Now, given

a quantum game scheme and two isomorphic classical games, we additionally

require the resulting quantum games to be isomorphic as well. We are concerned

with the Eisert-Wilkens-Lewenstein quantum game scheme and the strong

Establishing a quantum interface between different physical systems is of

special importance for developing the practical versatile quantum networks.

Entanglement between low- and high-lying atomic spin waves is essential for

building up Rydberg-based quantum information engineering, otherwhile be more

helpful to study the dynamics behavior of entanglement under external pertur-

bations. Here, we report on the successful storage of a single photon as a

high-lying atomic spin wave in quantum regime. Via storing a K-vector

Consecutive measurements performed on the same quantum system can reveal

fundamental insights into quantum theory's causal structure, and probe

different aspects of the quantum measurement problem. According to the

Copenhagen interpretation, measurements affect the quantum system in such a way

that the quantum superposition collapses after the measurement, erasing any

knowledge of the prior state. We show here that counter to this view,

unamplified measurements (measurements where all variables comprising a pointer

- Read more about Markovian and non-Markovian quantum measurements. (arXiv:1701.05636v1 [quant-ph])
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