We theoretically investigate the collisional heating of a cold atom system
subjected to time-periodic forces. We show within the Floquet framework that
this heating rate due to two-body collisions has a general semiclassical
expression $\mathcal{P}\propto \rho \sigma v_{\rm col} E_0$, depending on the
kinetic energy $E_0$ associated with the shaking, particle number density
$\rho$, elastic collision cross section $\sigma$, and an effective collisional
velocity $v_{\rm col}$ determined by the dominant energy scale in the system.

We study bound-state solutions of the Klein-Gordon equation
$\varphi^{\prime\prime}(x) =\big[m^2-\big(E-v\,f(x)\big)^2\big] \varphi(x),$
for bounded vector potentials which in one spatial dimension have the form
$V(x) = v\,f(x),$ where $f(x)\le 0$ is the shape of a finite symmetric central
potential that is monotone non-decreasing on $[0, \infty)$ and vanishes as
$x\rightarrow\infty.$ Two principal results are reported. First, it is shown
that the eigenvalue problem in the coupling parameter $v$ leads to spectral

We consider online algorithms with respect to the competitive ratio. Here, we
investigate quantum and classical one-way automata with non-constant size of
memory (streaming algorithms) as a model for online algorithms. We construct
problems that can be solved by quantum online streaming algorithms better than
by classical ones in a case of logarithmic or sublogarithmic size of memory.

Optimal (reversible) processes in thermodynamics can be modelled as
step-by-step processes, where the system is successively thermalized with
respect to different Hamiltonians by an external thermal bath. However, in
practice interactions between system and thermal bath will take finite time,
and precise control of their interaction is usually out of reach. Motivated by
this observation, we consider finite-time and uncontrolled operations between
system and bath, which result in thermalizations that are only partial in each

We suggest implementation of quantum teleportation protocol of unknown qubit
beyond Bell states formalism. Hybrid entangled state composed of coherent
components that belong to Alice and dual-rail single photon at Bob disposal is
used. Nonlinear effect on the teleported state is realized due to peculiarity
of interaction of coherent components with discrete variable state on a beam
splitter. Bob performs unitary transformation after receiving the appropriate

In this paper, we present a quantum algorithm for dynamic programming
approach for problems on directed acyclic graphs (DAGs). The running time of
the algorithm is $O(\sqrt{\hat{n}m}\log \hat{n})$, and the running time of the
best known deterministic algorithm is $O(n+m)$, where $n$ is the number of
vertices, $\hat{n}$ is the number of vertices with at least one outgoing edge;
$m$ is the number of edges. We show that we can solve problems that use OR,
AND, NAND, MAX and MIN functions as the main transition steps. The approach is

Logical inference leads to one of the major interpretations of probability
theory called logical interpretation, in which the probability is seen as a
measure of the plausibility of a logical statement under incomplete
information. In this paper, assuming that our usual inference procedure makes
sense for every set of logical propositions represented in terms of commuting
projectors on a given Hilbert space, we extend the logical interpretation to
quantum mechanics and derive the Born rule. Our result implies that, from the

The condition of phase matching prohibits the transfer of excitation from
free-space photons to surface plasmon polaritons (SPP). We propose and analyze
a scheme that excites an ensemble of emitters in a collective state, which is
phase matched with the SPP by the optical pulses used for its preparation. By a
collective enhancement the ensemble, hence, emits an SPP in a well defined
direction. We demonstrate the scheme by analyzing the launching of
near-infrared graphene SPP. Our theory incorporates the dispersive and

In this paper, we study the dynamical behavior and quantum metrology in a
rotating Nitrogen-Vacancy(NV) center system which is subject to an external
magnetic field. Based on the recently realized rapid rotation of nano-rotor [J.
Ahn, et. al., Phys. Rev. Lett. 121, 033603 (2018) and R. Reimann, et. al.,
Phys. Rev. Lett. 121, 033602 (2018)], the frequency of the rotation is close to
that of the intrinsic frequency of the NV center system, we predict the quantum

In this Letter, we experimentally demonstrate the first realization of weak
value amplification (WVA) using purely atomic degrees of freedom. Our
measurement model identifies the internal electronic states and external
motional states of a single trapped $^{40}$Ca$^+$ ion as the system degree and
pointer degree respectively, and their controllable weak coupling is provided
by a bichromatic light field. By performing appropriate postselection on the
internal states, a tiny position displacement of 4 angstroms of the trapped ion