The difficulty of simulating quantum dynamics depends on the norm of the
Hamiltonian. When the Hamiltonian varies with time, the simulation complexity
should only depend on this quantity instantaneously. We develop quantum
simulation algorithms that exploit this intuition. For the case of sparse
Hamiltonian simulation, the gate complexity scales with the $L^1$ norm
$\int_{0}^{t}\mathrm{d}\tau\left\lVert H(\tau)\right\lVert_{\max}$, whereas the
best previous results scale with $t\max_{\tau\in[0,t]}\left\lVert
We show that the cylindrical symmetry of the eigenvectors of the photon
position operator with commuting components, x, reflects the E(2) symmetry of
the photon little group. The eigenvectors of x form a basis of localized states
that have definite angular momentum, J, parallel to their common axis of
symmetry. This basis is well suited to the description of "twisted light" that
has been the subject of many recent experiments and calculations. Rotation of
the axis of symmetry of this basis results in the observed Berry phase
We study quantum anomaly detection with density estimation and multivariate
Gaussian distribution. Both algorithms are constructed using the standard
gate-based model of quantum computing. Compared with the corresponding
classical algorithms, the resource complexities of our quantum algorithm are
logarithmic in the dimensionality of quantum states and the number of training
quantum states. We also present a quantum procedure for efficiently estimating
the determinant of any Hermitian operators $\mathcal{A}\in\mathcal{R}^{N\times
Weyl points, synthetic magnetic monopoles in the 3D momentum space, are the
key features of topological Weyl semimetals. The observation of Weyl points in
ultracold atomic gases usually relies on the realization of high-dimensional
spin-orbit coupling (SOC) for two pseudospin states (% \textit{i.e.,}
spin-1/2), which requires complex laser configurations and precise control of
laser parameters, thus has not been realized in experiment. Here we propose
that robust Wely points can be realized using 1D triple-well superlattices
We probe electric-field noise in a surface ion trap for ion-surface distances
$d$ between 50 and 300 $\mu\mathrm{m}$ in the normal and planar directions. We
find the noise distance dependence to scale as $d^{-2.6}$ in our trap and a
frequency dependence which is consistent with $1/f$ noise. Simulations of the
electric-field noise specific to our trap geometry provide evidence that we are
not limited by technical noise sources. Our distance scaling data is consistent
The vast and growing number of publications in all disciplines of science
cannot be comprehended by a single human researcher. As a consequence,
researchers have to specialize in narrow sub-disciplines, which makes it
challenging to uncover scientific connections beyond the own field of research.
Thus access to structured knowledge from a large corpus of publications could
help pushing the frontiers of science. Here we demonstrate a method to build a
semantic network from published scientific literature, which we call SemNet. We
Mechanical modes are a potentially useful resource for quantum information
applications, such as quantum-level wavelength transducers, due to their
ability to interact with electromagnetic radiation across the spectrum. A
significant challenge for wavelength transducers is thermomechanical noise in
the mechanical mode, which pollutes the transduced signal with thermal states.
In this paper, we eliminate thermomechanical noise in the GHz-frequency
mechanical breathing mode of a piezoelectric optomechanical crystal using
Generalising the concept of Bell nonlocality to networks leads to novel forms
of correlations, the characterization of which is however challenging. Here we
investigate constraints on correlations in networks under the two natural
assumptions of no-signaling and independence of the sources. We consider the
``triangle network'', and derive strong constraints on correlations even though
the parties receive no input, i.e. each party performs a fixed measurement. We
Two time-reversal quantum key distribution (QKD) schemes are the quantum
entanglement based device-independent (DI)-QKD and
measurement-device-independent (MDI)-QKD. The recently proposed twin field
(TF)-QKD, also known as phase-matching (PM)-QKD, has improved the key rate
bound from $O\left( \eta \right )$ to $O\left( \sqrt {\eta} \right )$ with
$\eta$ the channel transmittance. In fact, TF-QKD is a kind of MDI-QKD but
based on single-photon detection. In this paper, we propose a different PM-QKD
We address the standard quantum error correction using the three-qubit
bit-flip code, yet in continuous-time. This entails rendering a target manifold
of quantum states globally attractive. Previous feedback designs could feature
spurious equilibria, or resort to discrete kicks pushing the system away from
these equilibria to ensure global asymptotic stability. We present a new
approach that consists of introducing controls driven by Brownian motions.
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