Quantum Preprints

We study ultrafast ionization dynamics using orthogonally polarized two-color (OTC) laser pulses involving the resonant "first plus second" ($omega+2omega$) scheme. The scheme is illustrated by numerical simulations of the time-dependent Schr"odinger equation and recording the photoelectron momentum distribution. On the basis of the simulations of this resonant ionization, we identify... Read more
Published on: 2019-12-16
We show that entangled Gaussian states can falsely appear as product states when the (unphysical) limit of infinite squeezing is used in the cluster state formalism: strong squeezing cannot be tantamount to infinite squeezing because the latter entails too large a degree of symmetry, which can be misleading and fail... Read more
Published on: 2019-12-16
Quantum mechanics has irked physicists ever since its conception more than 100 years ago. While some of the misgivings, such as it being unintuitive, are merely aesthetic, quantum mechanics has one serious shortcoming: it lacks a physical description of the measurement process. This "measurement problem" indicates that quantum mechanics is... Read more
Published on: 2019-12-16
Current implementations of quantum computers suffer from large numbers of control lines per qubit, becoming unmanageable with system scale up. Here, we discuss a sparse spin-qubit architecture featuring integrated control electronics significantly reducing the off-chip wire count. This quantum-classical hardware integration closes the feasibility gap towards a CMOS quantum computer.... Read more
Published on: 2019-12-16
Optical modes possessing orbital angular momentum constitute a very useful platform for experimental studies on the quantum limits of thermodynamics. Here, we present experimental results for entangled photon pairs subjected to thin turbulence as a thermodynamical process. By measuring the orbital angular momentum correlations, we investigate Jarzynski equality for single... Read more
Published on: 2019-12-16
The most unstable quantum states and elementary particles possess more than a single decay channel. At the same time, it is well known that typically the decay law is not simply exponential. Therefore, it is natural to ask how to spot the non-exponential decay when (at least) two decay channels... Read more
Published on: 2019-12-16
Effects of non-linear coupling between the system and the bath vibrational modes on the system internal conversion dynamics are investigated using the Dirac-Frenkel variational approach with the defined sD2 ansatz. It explicitly accounts for the entangled system electron-vibrational wavepacket states, while the bath quantum harmonic oscillator (QHO) states are expanded... Read more
Published on: 2019-12-16
The Bell's theorem stands as an insuperable roadblock in the path to a very desired intuitive solution of the Einstein-Podolsky-Rosen paradox and, hence, it lies at the core of the current lack of a clear interpretation of the quantum formalism. The theorem states through an experimentally testable inequality that the... Read more
Published on: 2019-12-16
It is known that several sub-universal quantum computing models, such as the IQP model, the Boson sampling model, the one-clean qubit model, and the random circuit model, cannot be classically simulated in polynomial time under certain conjectures in classical complexity theory. Recently, these results have been improved to "fine-grained" versions... Read more
Published on: 2019-12-16
Polarization maintenance is a key technology for free-space quantum communication. In this paper, we describe a polarization maintenance design of a transmitting antenna with an average polarization extinction ratio of 887 : 1 by a local test. We implemented a feasible polarization-compensation scheme for satellite motions that has a polarization... Read more
Published on: 2019-12-16