Quantum Preprints

We discuss how the language of wave functions (state vectors) and associated non-commuting Hermitian operators naturally emerges from classical mechanics by applying the inverse Wigner-Weyl transform to the phase space probability distribution and observables. In this language, the Schr"odinger equation follows from the Liouville equation, with $hbar$ now a free... Read more
Published on: 2020-12-10
We show that given the order of a single element selected uniformly at random from $mathbb Z_N^*$, we can with very high probability, and for any integer $N$, efficiently find the complete factorization of $N$ in polynomial time. This implies that a single run of the quantum part of Shor's... Read more
Published on: 2020-12-10
The teleportation model of quantum computation introduced by Gottesman and Chuang (1999) motivated the development of the Clifford hierarchy. Despite its intrinsic value for quantum computing, the widespread use of magic state distillation, which is closely related to this model, emphasizes the importance of comprehending the hierarchy. There is currently... Read more
Published on: 2020-12-10
Motivated by the recent success of tensor networks to calculate the residual entropy of spin ice and kagome Ising models, we develop a general framework to study frustrated Ising models in terms of infinite tensor networks %, i.e. tensor networks that can be contracted using standard algorithms for infinite systems.... Read more
Published on: 2020-12-10
For symmorphic crystalline interacting gapped systems we derive a classification under adiabatic evolution. This classification is complete for non-degenerate ground states. For the degenerate case we discuss some invariants given by equivariant characteristic classes. We do not assume an emergent relativistic field theory nor that phases form a topological spectrum.... Read more
Published on: 2020-12-10
Control over transition rates between spin states of emitters is crucial in a wide variety of fields ranging from quantum information science to the nanochemistry of free radicals. We present an approach to drive a both electric and magnetic dipole-forbidden transition of a spin emitter by placing it in a... Read more
Published on: 2020-12-10
Detector backaction can be completely evaded when the state of a one-electron quantum cyclotron is detected, but it nonetheless significantly broadens the quantum-jump resonance lineshapes from which the cyclotron frequency can be deduced. This limits the accuracy with which the electron magnetic moment can be determined to test the standard... Read more
Published on: 2020-12-10
In this paper, we present an interpolation scheme for FRQI images based on bilinear interpolation. To accomplish this, we formulated several quantum modules, i.e., assignment module, increment module, and quarter module, and suffused them into our proposed quantum image interpolation circuit. The concrete quantum circuits to accomplish up-scaling and down-scaling... Read more
Published on: 2020-10-21
The second quantum revolution has been built on a foundation of fundamental research at the intersection of physics and information science, giving rise to the discipline we now call Quantum Information Science (QIS). The quest for new knowledge and understanding drove the development of new experimental tools and rigorous theory,... Read more
Published on: 2020-10-21
Quantum entanglement is a fundamental property of coherent quantum states and an essential resource for quantum computing. While two-qubit entanglement has been demonstrated for spins in silicon, creation of multipartite entanglement, a first step toward implementing quantum error correction, has remained challenging due to the difficulties in controlling a multi-qubit... Read more
Published on: 2020-10-21
We consider the fate of $1/N$ expansions when a many-body quantum system is quenched across criticality and show the emergence of ${rm e}^{2lambda t}/N$ as renormalized parameter ruling the quantum-classical transition and accounting non-perturbatively for the local divergence rate $lambda$ of mean-field solutions. In terms of ${rm e}^{2lambda t}/N$, quasiclassical... Read more
Published on: 2020-10-21
Recently, Tsai et al. (Laser Phys. Lett. 17, 075202, 2020) proposed a lightweight authenticated semi-quantum key distribution protocol for a quantum participant to share a secret key with a classical participant. However, this study points out that an attacker can use a modification attack to make both participants share a... Read more
Published on: 2020-10-21
These are the lecture notes used in the course Understanding Quantum Chemistry for 1st year master chemistry at the Vrije Universiteit Amsterdam. The schedule is 2 weeks on HF and 2 weeks on DFT, which provides a quite rough ride for the the students. The lecture notes also include exercises.... Read more
Published on: 2020-10-21
Non-Hermitian systems can produce branch singularities known as exceptional points (EPs). The topological properties of an EP can involve either the winding of eigenvalues that produces a discriminant number (DN) or the eigenvector holonomy that generates a Berry phase, making them richer than typical degenerate points in Hermitian systems. However,... Read more
Published on: 2020-10-21
Quantum engineering using photonic structures offer new capabilities for atom-photon interactions for quantum optics and atomic physics, which could eventually lead to integrated quantum devices. Despite the rapid progress in the variety of structures, coherent excitation of the motional states of atoms in a photonic waveguide using guided modes has... Read more
Published on: 2020-10-21
Quantum error mitigation techniques are at the heart of quantum computation. Conventional quantum error correction codes are promising solutions, while they become infeasible in the noisy intermediate scale quantum (NISQ) era, hurdled by the required expensive resources. The variational quantum learning scheme (VQLS), which is composed of trainable quantum circuits... Read more
Published on: 2020-10-21
Controlling and narrowing x-ray frequency spectra in magnetically perturbed two-target nuclear forward scattering is theoretically studied. Our system is composed of two $^{57}$FeBO$_3$ crystals applied with external magnetic fields and illuminated by broadband x-ray synchrotron radiation pulses of 14.4 keV central photon energy. Combinations of switching individual magnetic field lead... Read more
Published on: 2020-10-21
Diamond nitrogen-vacancy (NV) center magnetometry has recently received considerable interest from researchers in the fields of applied physics and sensors. The purpose of this review is to analyze the principle, sensitivity, technical development potential, and application prospect of the diamond NV center magnetometry. This review briefly introduces the physical characteristics... Read more
Published on: 2020-10-21
For the identification of non-trivial quantum phase, we exploit a Bell-type correlation that is applied to the one-dimensional spin-1 XXZ chain. It is found that our generalization of bipartite Bell correlation can take a decomposed form of transverse spin correlation together with high-order terms. The formulation of density-matrix renormalisation group... Read more
Published on: 2020-10-21
The correspondence principle is a cornerstone in the entire construction of quantum mechanics. This principle has been recently challenged by the observation of an early-time exponential increase of the out-of-time-ordered correlator (OTOC) in classically non-chaotic systems [E.B. Rozenbaum et al., Phys. Rev. Lett. 125, 014101 (2020)], Here we show that... Read more
Published on: 2020-10-21