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Entanglement entropy in topologically ordered matter phases has been computed

extensively using various methods. In this paper, we study the entanglement

entropy of topological phases in two-spaces from a new perspective---the

perspective of quasiparticle fluctuations. In this picture, the entanglement

spectrum of a topologically ordered system is identified with the spectrum of

quasiparticle fluctuations of the system, and the entanglement entropy measures

the maximal quasiparticle fluctuations on the EB. As a consequence,

Current approaches to quantum gravity suggest there should be a modification

of the standard quantum mechanical commutator, $[{\hat x} , {\hat p}] = i

\hbar$. Typical modifications are phenomenological and designed to result in a

minimal length scale. As a motivating principle for the modification of the

position and momentum commutator, we assume the validity of a version of the

Bender-Brody-M\"uller variant of the Berry-Keating approach to the Riemann

Modern neuroscience is currently limited in its capacity to perform long

term, wide-field measurements of neuron electromagnetics with nanoscale

resolution. Quantum microscopy using the nitrogen vacancy centre (NV) can

provide a potential solution to this problem with electric and magnetic field

sensing at nano-scale resolution and good biocompatibility. However, the

performance of existing NV sensing technology does not allow for studies of

small mammalian neurons yet. In this paper, we propose a solution to this

In a couple of recent preprints Moldoveanu has suggested that there are

errors in my disproof of Bell's theorem. Here I show that this claim is false.

In particular, I show that my local-realistic framework is incorrectly and

misleadingly presented in both of his preprints. In addition there are a number

of serious mathematical and conceptual errors in his discussion of my

framework. For example, contrary to his claim, my framework is manifestly

non-contextual. In particular, quantum correlations are understood within it as

The efficient creation and detection of spatial modes of light has become

topical of late, driven by the need to increase photon-bit-rates in classical

and quantum communications. Such mode creation/detection is traditionally

achieved with tools based on linear optics. Here we put forward a new spatial

mode detection technique based on the nonlinear optical process of

sum-frequency generation. We outline the concept theoretically and demonstrate

it experimentally with intense laser beams carrying orbital angular momentum

We implement the reinforcement learning agent for a spin-1 atomic system to

prepare spin squeezed state from given initial state. Proximal policy gradient

(PPO) algorithm is used to deal with continuous external control field and

final optimized protocol is given by a stochastic policy. In both mean-field

system and two-body quantum system, RL agent finds the optimal policies. In

many-body quantum system, it also gives polices that outperform purely greedy

Studying the time development of the expectation value in the

future-not-included complex action theory, we point out that the momentum

relation (the relation analogous to $p=\frac{\partial L}{\partial \dot{q}}$),

which was derived via the Feynman path integral and was shown to be correct in

the future-included theory in our previous papers, is not valid in the

future-not-included theory. We provide the correct momentum relation in the

future-not-included theory, and argue that the future-not-included classical

The Wigner function's behavior of accelerated and non-accelerated Greenberger

Horne Zeilinger (GHZ) state is discussed. For the non-accelerated GHZ state,

the minimum/maximum peaks of the Wigner function depends on the distribution's

angles, where they are displayed regularly at fixed values of the

distribution's angles. We show that, for the accelerated GHZ state, the minimum

bounds increases as the acceleration increases. The increasing rate depends on

We present an alternative method for determining the sound velocity in atomic

Bose-Einstein condensates, based on thermodynamic global variables. The total

number of trapped atoms was as a function of temperature carefully studied

across the phase transition, at constant volume. It allowed us to evaluate the

sound velocity resulting in consistent values from the quantum to classical

regime, in good agreement with previous results found in literature. We also

Witness operators are a central tool to detect entanglement or to distinguish

among the different entanglement classes of multiparticle systems, which can be

defined using stochastic local operations and classical communication (SLOCC).

We show a one-to-one correspondence between general SLOCC witnesses and a class

of entanglement witnesses in an extended Hilbert space. This relation can be

used to derive SLOCC witnesses from criteria for full separability of quantum