Latest in quant-ph

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Assembly of 2N entangled fermions into multipartite composite bosonsFeb 21 2019An even number of fermions can behave in a bosonic way. The simplest scenario involves two fermions which can form a single boson. But four fermions can either behave as two bipartite bosons or further assemble into a single four-partite bosonic molecule. ... More
Ultralow-field Nuclear Magnetic Resonance Asymmetric SpectroscopyFeb 21 2019Ultralow-field nuclear magnetic resonance (NMR) provides a new regime for many applications ranging from materials science to fundamental physics. However, the experimentally observed spectra show asymmetric amplitudes, differing greatly from those predicted ... More
Paths, negative "probabilities", and the Leggett-Garg inequalitiesFeb 21 2019We present a path analysis of the condition under which the outcomes of previous observation affect the results of the measurements yet to be made. It is shown that this effect, also known as "signalling in time", occurs whenever the earlier measurements ... More
Pseudo-2D superconducting quantum computing circuit for the surface codeFeb 21 2019Of the many potential hardware platforms, superconducting quantum circuits have become the leading contender for constructing a scalable quantum computing system. All current architecture designs necessitate a 2D arrangement of superconducting qubits ... More
Finding Hadamard matrices by a quantum annealing machineFeb 21 2019Finding a Hadamard matrix (H-matrix) among the set of all binary matrices of corresponding order is a hard problem. We propose a method to formulate the Hamiltonian of finding H-matrix problem and address its implementation limitation on existing quantum ... More
Optimal Coherent Filtering for Single Noisy PhotonsFeb 20 2019We introduce a filter using a noise-free quantum buffer with large optical bandwidth that can both filter temporal-spectral modes, as well as inter-convert them and change their frequency. We show that such quantum buffers optimally filter out temporal-spectral ... More
Continuous symmetries and approximate quantum error correctionFeb 20 2019Quantum error correction and symmetry arise in many areas of physics, including many-body systems, metrology in the presence of noise, fault-tolerant computation, and holographic quantum gravity. Here we study the compatibility of these two important ... More
Optimized cavity-mediated dispersive two-qubit gates between spin qubitsFeb 20 2019The recent realization of a coherent interface between a single electron in a silicon quantum dot and a single photon trapped in a superconducting cavity opens the way for implementing photon-mediated two-qubit entangling gates. In order to couple a spin ... More
A dynamical proof of the second law of thermodynamicsFeb 20 2019We provide a dynamical proof of the second law of thermodynamics, along the lines of an argument of Penrose and Gibbs, making crucial use of the upper semicontinuity of the mean entropy proved by Robinson and Ruelle and Lanford and Robinson. An example ... More
Transferring the quantum state of electrons across a Fermi sea with Coulomb interactionFeb 20 2019The Coulomb interaction generally limits the quantum propagation of electrons. However, it can also provide a mechanism to transfer their quantum state over larger distances. Here, we demonstrate such a form of teleportation, across a metallic island ... More
Sublogarithmic behaviour of the entanglement entropy in fermionic chainsFeb 20 2019In this paper, we discuss the possibility of unexplored behaviours for the entanglement entropy in extended quantum systems. Namely, we study the R\'enyi entanglement entropy for the ground state of long-range Kitaev chains with slow decaying couplings. ... More
Thermodynamic Quantum Time CrystalsFeb 20 2019Investigation of states with a periodic time dependence of physical quantities attracts a considerable interest now. Although it has been proposed initially that such states (coined Quantum Time Crystals) might be macroscopic and thermodynamically stable, ... More
Comment on 'Winding around non-Hermitian singularities' by Zhong et al., Nat. Commun. 9, 4808 (2018)Feb 20 2019In a recent paper entitled "Winding around non-Hermitian singularities" by Zhong et al., published in Nat. Commun. 9, 4808 (2018), a formalism is proposed for calculating the permutations of eigenstates that arise upon encircling (multiple) exceptional ... More
Quantum convolutional data-syndrome codesFeb 20 2019We consider performance of a simple quantum convolutional code in a fault-tolerant regime using several syndrome measurement/decoding strategies and three different error models, including the circuit model.
Nanostructuring of LNOI for efficient edge couplingFeb 20 2019We present the design, fabrication and characterization of LNOI fiber-to-chip inverse tapers for efficient edge coupling. The etching characteristics of various LNOI crystal cuts are investigated for the realization of butt-coupling devices. We experimentally ... More
Quantum Position-Dependent Mass and Smooth Boundary Forces from Constrained GeometriesFeb 19 2019We implement the so-called Weyl-Heisenberg covariant integral quantization in the case of a classical system constrained by a bounded or semi-bounded geometry. The procedure, which is free of the ordering problem of operators, is illustrated with the ... More
Non-Hermitian Boundary ModesFeb 19 2019We consider conditions for the existence of boundary modes in non-Hermitian systems with edges of arbitrary co-dimension. Through a universal formulation of the formation criteria for boundary modes in terms of local Green functions, we outline a generic ... More
Finite-size criteria for spectral gaps in $D$-dimensional quantum spin systemsFeb 19 2019We generalize the existing finite-size criteria for spectral gaps of frustration-free spin systems to $D>2$ dimensions. We obtain a local gap threshold of $\frac{3}{n}$, independent of $D$, for nearest-neighbor interactions. The $\frac{1}{n}$ scaling ... More
A functional renormalization group approach to thermodynamics of weakly interacting Bose gases: from linear to hydrodynamic fluctuationsFeb 19 2019We study weakly interacting Bose gases using the functional renormalization group with a hydrodynamic effective action. We use a scale-dependent parametrization of the boson fields developed previously that interpolates between a Cartesian representation ... More
Sub-ns timing accuracy for satellite quantum communicationsFeb 19 2019Satellite quantum communications have rapidly evolved in the past few years, culminating in the proposal, development, and deployment of satellite missions dedicated to quantum key distribution and the realization of fundamental tests of quantum mechanics ... More
Entropies for Coupled Harmonic Oscillators and TemperatureFeb 19 2019We study two entropies of a system composed of two coupled harmonic oscillators which is brought to a canonical thermal equilibrium with a heat-bath at temperature $T$. Using the purity function, we explicitly determine the R\'enyi and van Newmon entropies ... More
Machine learning of Markovian embedding for non-Markovian quantum dynamicsFeb 19 2019Machine learning methods have proved to be useful for the recognition of patterns in statistical data. The measurement outcomes are intrinsically random in quantum physics, however they do have a pattern when the measurements are performed successively ... More
Hong-Ou-Mandel interferometry on a biphoton beat noteFeb 19 2019Hong-Ou-Mandel interference, the fact that identical photons that arrive simultaneously on different input ports of a beam splitter bunch into a common output port, can be used to measure optical delays between different paths. It is generally assumed ... More
Entanglement Stabilization using Parity Detection and Real-Time Feedback in Superconducting CircuitsFeb 19 2019Feb 20 2019Fault tolerant quantum computing relies on the ability to detect and correct errors, which in quantum error correction codes is typically achieved by projectively measuring multi-qubit parity operators and by conditioning operations on the observed error ... More
Thermal emission from semi-classical dynamical systemFeb 19 2019Recently the bound on the Lyapunov exponent $\lambda_L \le 2\pi T/ \hbar$ in thermal quantum systems was conjectured by Maldacena, Shenker and Stanford. If we naively apply this bound to a system with a fixed Lyapunov exponent $\lambda_L$, it might predict ... More
Beating the fundamental rate-distance limit in a proof-of-principle quantum key distribution systemFeb 19 2019With the help of quantum key distribution (QKD), two distant peers are able to share information-theoretically secure key bits. Increasing key rate is ultimately significant for the applications of QKD in lossy channel. However, it has proved that there ... More
Electric quadrupole moment and the tensor magnetic polarizability of twisted electrons and a potential for their measurementsFeb 19 2019For a twisted (vortex) Dirac particle in nonuniform electric and magnetic fields, the relativistic Foldy-Wouthuysen Hamiltonian is derived including high order terms describing new effects. The result obtained shows for the first time that a twisted spin-1/2 ... More
Error reduction of quantum algorithmsFeb 19 2019We give a technique to reduce the error probability of quantum algorithms that determine whether its input has a specified property of interest. The standard process of reducing this error is statistical processing of the results of multiple independent ... More
Improving the quantum annealing of the ferromagnetic $ p $-spin model through pausingFeb 18 2019The probability of success of quantum annealing can be improved significantly by pausing the annealer during its dynamics, exploiting thermal relaxation in a controlled fashion. In this paper, we investigate the effect of pausing the quantum annealing ... More
A Quantum IP Predictor-Corrector Algorithm for Linear ProgrammingFeb 18 2019We introduce a new quantum optimization algorithm for Linear Programming (LP) problems based on Interior Point (IP) Predictor-Corrector (PC) methods whose (worst case) time complexity is $O(\sqrt{n}Ls^3 k \epsilon^{-1}\epsilon_s^{-1}) $. This represents ... More
Seeing in complete darkness, using the Unruh effectFeb 18 2019We present a new method by which, in principle, it is possible to "see in absolute darkness", i.e., without exchanging any real quanta through quantum fields. This is possible because objects modify the mode structure of the vacuum in their vicinity. ... More
Magnetic Field Control of Optical Transmission and Narrow Linewidth Superradiant Lasing by Strontium AtomsFeb 18 2019We study the magnetic field controlled optical transmission observed in [Phys. Rev. Lett. 118, 263601 (2017)] with ultra-cold ${}^{88} {\rm Sr}$ atoms trapped in a one-dimensional optical lattice inside an optical cavity. We show that this phenomenon ... More
Helical transport in coupled resonator waveguidesFeb 18 2019We show that a synthetic pseudospin-momentum coupling can be used to design quasi-one-dimensional disorder-resistant coupled resonator optical waveguides (CROW). In this structure, the propagating Bloch waves exhibit a pseudospin-momentum locking at specific ... More
A Combinatorial Approach to Causal InferenceFeb 18 2019The objective of causal inference is to learn the network of causal relationships holding between a system of variables from the correlations that these variables exhibit; a sub-problem of which is to certify whether or not a given causal hypothesis is ... More
Quantum Storage of Frequency-Multiplexed Heralded Single PhotonsFeb 18 2019We report on the quantum storage of a heralded frequency-multiplexed single photon in an integrated laser-written rare-earth doped waveguide. The single photon contains 15 discrete frequency modes separated by 261 MHz and spaning across 4 GHz. It is obtained ... More
Proving ErasureFeb 18 2019It seems impossible to certify that a remote hosting service does not leak its users' data --- or does quantum mechanics make it possible? We investigate if a server hosting data can information-theoretically prove its definite deletion using a "BB84-like" ... More
Phase transition in complex-time Loschmidt echo of short and long range spin chainFeb 18 2019We explain and exploit the random matrix formulation of the Loschmidt echo for the XX spin chain, valid for multiple domain wall initial states and also for a XX spin chain generalized with additional interactions to more neighbours. For models with interactions ... More
Emergent perturbation independent decay of the Loschmidt echo in a many-spin system studied through scaled dipolar dynamicsFeb 18 2019Evaluating the role of perturbations versus the intrinsic coherent dynamics in driving to equilibrium is of fundamental interest to understand quantum many-body thermalization, in the quest to build ever complex quantum devices. Here we introduce a protocol ... More
Quantum bus building-block for a scalable quantum computer architectureFeb 18 2019In superconducting quantum computers, qubits are usually only coupled to their nearest-neighbors. To overcome this limitation, we propose a scalable architecture to simultaneously connect several pairs of distant logical qubits via a dispersively coupled ... More
Memory cost of temporal correlationsFeb 18 2019A possible notion of nonclassicality for single systems can be defined on the basis of the notion of memory cost of classically simulating probabilities observed in a temporal sequence of measurements. We further explore this idea in a theory-independent ... More
Quantum supercapacitorsFeb 18 2019Recently there has been a great deal of interest on the possibility to exploit quantum-mechanical effects to increase the performance of energy storage systems. Here we introduce and solve a model of a quantum supercapacitor. This consists of two chains, ... More
Information-theoretic lower bounds for quantum sortingFeb 18 2019We analyze the quantum query complexity of sorting under partial information. In this problem, we are given a partially ordered set $P$ and are asked to identify a linear extension of $P$ using pairwise comparisons. For the standard sorting problem, in ... More
Temporal Wheeler's delayed-Choice Experiment based on Cold Atomic Quantum MemoryFeb 18 2019Nowadays the most intriguing features of wave particle complementarity of single photon is exemplified by the famous Wheeler's delayed choice experiment in linear optics, nuclear magnetic resonance and integrated photonic device systems. Studying the ... More
High harmonic generation under dynamical confinement: An atom-in-box modelFeb 18 2019We consider optical high harmonic generation in a hydrogen atom confined in a breathing spherical box by considering atomic nucleus as fixed at the center of sphere. In such spherically symmetric, dynamical trap, the high harmonic generation spectrum ... More
Level shift and decay dynamics of a quantum emitter around plasmonic nanostructureFeb 18 2019We put forward a general approach for calculating the quantum energy level shift for emitter in arbitrary nanostructures, in which the energy level shift is expressed by the sum of the real part of the scattering photon Green function (GF) and a simple ... More
Micromotion-Enhanced Fast Entangling Gates For Trapped Ion Quantum ComputingFeb 18 2019RF-induced micromotion in trapped ion systems is typically minimised or circumvented to avoid off-resonant couplings for adiabatic processes such as multi-ion gate operations. Non-adiabatic entangling gates (so-called `fast gates') do not require resolution ... More
Resolving Phonon Fock States in a Multimode Cavity with a Double-Slit QubitFeb 17 2019We resolve phonon number states in the spectrum of a superconducting qubit coupled to a multimode acoustic cavity. Crucial to this resolution is the sharp frequency dependence in the qubit-phonon interaction engineered by coupling the qubit to surface ... More
A synthetic gauge field for two-dimensional time-multiplexed quantum random walksFeb 17 2019Temporal multiplexing provides an efficient and scalable approach to realize a quantum random walk with photons that can exhibit topological properties. But two dimensional time-multiplexed topological quantum walks studied so far have relied on generalizations ... More
Many-body cooperative effects in an ensemble of point-like impurity centers near a charged conductive surfaceFeb 17 2019On the basis of a quantum microscopic approach we study the cooperative effects induced by the dipole-dipole interaction in an ensemble of point-like impurity centers located near a charged perfectly conducting surface. We analyze the simultaneous influence ... More
Focus on Shortcuts to AdiabaticityFeb 17 2019Shortcuts to Adiabaticity (STA) constitute driving schemes that provide an alternative to adiabatic protocols to control and guide the dynamics of classical and quantum systems without the requirement of slow driving. Research on STA advances swiftly ... More
Experimental Twin-Field Quantum Key Distribution Through Sending-or-Not-SendingFeb 17 2019Channel loss seems to be the most severe limitation to the application long distance quantum key distribution in practice. The idea of twin-field quantum key distribution can improve the key rate from the linear scale of channel loss in the traditional ... More
Localized states of Dirac equationFeb 17 2019In this paper, we introduce an extension of the Dirac equation, very similar to Dirac oscillator, that gives stationary localized wave packets as eigenstates of the equation. The extension to the Dirac equation is achieved through the replacement of the ... More
A Reed Muller-based approach for optimization of general binary quantum multiplexersFeb 17 2019Previous work has provided methods for decomposing unitary matrices to series of quantum multiplexers, but the multiplexers created in this way are highly non-minimal. This paper presents a new approach for optimizing quantum multiplexers with arbitrary ... More
An optomechanical platform with a 3-dimensional waveguide cavityFeb 17 2019At low temperatures, microwave cavities are often preferred for the readout and control of a variety of systems. In this paper, we present design and measurements on an optomechanical device based on a 3-dimensional rectangular waveguide cavity. We show ... More
Hyperpolarized relaxometry based nuclear T1 noise spectroscopy in hybrid diamond quantum registersFeb 17 2019Understanding the origins of spin lifetimes in hybrid quantum systems is a matter of current importance in several areas of quantum information and sensing. Methods that spectrally map spin relaxation processes provide insight into their origin and can ... More
Implications of non-Markovian dynamics on information-driven engineFeb 16 2019The understanding of memory effects arising from the interaction between system and environment is a key for engineering quantum thermodynamic devices beyond the standard Markovian limit. We study the performance of measurement-based thermal machine whose ... More
Phase transition in a noisy Kitaev toric code modelFeb 16 2019It is well-known that the partition function of a classical spin model can be mapped to a quantum entangled state where some properties on one side can be used to find new properties on the other side. However, the consequences of the existence of a classical ... More
A C*-algebraic approach to interacting quantum field theoriesFeb 16 2019A novel C*-algebraic framework is presented for relativistic quantum field theories, fixed by a Lagrangean. It combines the postulates of local quantum physics, encoded in the Haag-Kastler axioms, with insights gained in the perturbative approach to quantum ... More
Quasiprobability distribution functions from fractional Fourier transformsFeb 16 2019We show, in a formal way, how a class of complex quasiprobability distribution functions may be introduced by using the fractional Fourier transform. This leads to the Fresnel transform of a characteristic function instead of the usual Fourier transform. ... More
Questions on the Structure of Perfect Matchings inspired by Quantum PhysicsFeb 16 2019We state a number of related questions on the structure of perfect matchings. Those questions are inspired by and directly connected to Quantum Physics. In particular, they concern the constructability of general quantum states using modern photonic technology. ... More
Ultraviolet Fabry-Perot cavity with stable finesse under ultrahigh vacuum conditionsFeb 15 2019We have constructed an apparatus containing a linear ion trap and a high-finesse optical cavity in the ultraviolet spectral range. In our construction, we have avoided all organic materials inside the ultrahigh vacuum chamber. We show that, unlike previously ... More
Deterministic integration of single nitrogen-vacancy centers into nanopatch antennasFeb 15 2019Quantum emitters coupled to plasmonic nanoantennas produce single photons at unprecedentedly high rates in ambient conditions. This enhancement of quantum emitters' radiation rate is based on the existence of optical modes with highly sub-diffraction ... More
Swift heat transfer by fast-forward driving in open quantum systemsFeb 15 2019Typically, time-dependent thermodynamic protocols need to run asymptotically slowly in order to avoid dissipative losses. By adapting ideas from counter-diabatic driving and Floquet engineering to open systems, we develop fast-forward protocols for swiftly ... More
Bayesian ACRONYM TuningFeb 15 2019We provide an algorithm that uses Bayesian randomized benchmarking in concert with a local optimizer, such as SPSA, to find a set of controls that optimizes that average gate fidelity. We call this method Bayesian ACRONYM tuning as a reference to the ... More
On exponential stabilization of N-level quantum angular momentum systemsFeb 15 2019In this paper, we consider the feedback stabilization problem for N-level quantum angular momentum systems undergoing continuous-time measurements. By using stochastic and geometric control tools, we provide sufficient conditions on the feedback control ... More
Non-Local Parity Measurements and the Quantum Pigeonhole EffectFeb 15 2019The pigeonhole principle upholds the idea that by ascribing to three different particles either one of two properties, we necessarily end up in a situation when at least two of the particles have the same property. In quantum physics, this principle is ... More
Device-independent tests of structures of measurement incompatibilityFeb 15 2019In contrast with classical physics, in quantum physics some sets of measurements are incompatible in the sense that they can not be performed simultaneously. Among other applications, incompatibility allows for contextuality and Bell nonlocality. This ... More
Causally neutral quantum physicsFeb 15 2019In fundamental theories that accounts for quantum gravitational effects, the spacetime causal structure is expected to be quantum uncertain. Previous studies of quantum causal structure focused on finite-dimensional systems. Here we present an algebraic ... More
Magnetization and entanglement after a geometric quench in the XXZ chainFeb 15 2019We investigate the dynamics of the XXZ spin chain after a geometric quench, which is realized by connecting two half-chains prepared in their ground states with zero and maximum magnetizations, respectively. The profiles of magnetization after the subsequent ... More
Applying Multi-qubit Correction to Frustrated Cluster Loops on an Adiabatic Quantum ComputerFeb 15 2019The class of problems represented by frustrated cluster loops, FCL, is a robust set of problems that spans a wide range of computational difficulty and that are easy to determine what their solutions are. Here, we use frustrated cluster loops to test ... More
Periodic thermodynamics of the Rabi model with circular polarization for arbitrary spin quantum numbersFeb 15 2019We consider a spin $s$ subjected to both a static and an orthogonally applied oscillating, circularly polarized magnetic field while being coupled to a heat bath, and analytically determine the quasi\-stationary distribution of its Floquet-state occupation ... More
Effects of decoherence on diabatic errors in Majorana braidingFeb 15 2019The braiding of two non-Abelian Majorana modes is important for realizing topological quantum computation. It can be achieved through tuning the coupling between the two Majorana modes to be exchanged and two ancillary Majorana modes. However, this coupling ... More
Mean-field phase diagram of ultracold atomic gases in cavity quantum electrodynamicsFeb 15 2019We investigate the mean-field phase diagram of the Bose-Hubbard model with infinite-range interactions in two dimensions. This model describes ultracold bosonic atoms confined by a two-dimensional optical lattice and dispersively coupled to a cavity mode ... More
Ultrastrong Jaynes-Cummings ModelFeb 15 2019We propose a reliable scheme to realize the ultrastrong Jaynes-Cummings (JC) model by simultaneously modulating the resonance frequencies of the two-level system and the bosonic mode in the ultrastrong quantum Rabi model. We find that in both the high- ... More
Enhancement of coherent dipole coupling between two atoms via squeezing a cavity modeFeb 15 2019We propose a theoretical method to enhance the coherent dipole coupling between two atoms in an optical cavity via parametrically squeezing the cavity mode. In the present scheme, conditions for coherent coupling are derived in detail and diverse dynamics ... More
Long-distance entangling gates between quantum dot spins mediated by a superconducting resonatorFeb 15 2019Recent experimental work with silicon qubits has shown that it is possible, using an inhomogeneous magnetic field, to strongly couple modes of a microwave resonator to the spin of a single electron trapped in a double quantum dot. This suggests the possibility ... More
Two-dimensional nanoscale nuclear magnetic resonance spectroscopy enhanced by artificial intelligenceFeb 15 2019Two-dimensional Nuclear Magnetic Resonance (NMR) is essential to molecule structure determination. Nitrogen vacancy (NV) center in diamond has been proposed and developed as an outstanding quantum sensor to realize NMR in nanoscale. However, it is still ... More
Quantum Information Capsule in Multiple-Qudit Systems and Continuous-Variable SystemsFeb 15 2019Quantum correlations in an entangled many-body system are capable of storing information. Even when the information is injected by a local unitary operation to the system, the entanglement delocalizes it. In a recent study on multiple-qubit systems, it ... More
Memory effects teleportation of quantum Fisher information under decoherenceFeb 15 2019We have investigated how memory effects on the teleportation of quantum Fisher information(QFI) for a single qubit system using a class of X-states as resources influenced by decoherence channels with memory, including amplitude damping, phase-damping ... More
Quantum Simulation of Resonant Transitions for Solving the Eigen-problem of an Effective Water HamiltonianFeb 14 2019It is difficult to calculate the energy levels and eigenstates of a large physical system on a classical computer because of the exponentially growing size of the Hilbert space. In this work, we experimentally demonstrate a quantum algorithm which could ... More
A quantum compiler for qudits of prime dimension greater than 3Feb 14 2019Prevailing proposals for the first generation of quantum computers make use of 2-level systems, or qubits, as the fundamental unit of quantum information. However, recent innovations in quantum error correction and magic state distillation protocols demonstrate ... More
Quantum Measurements and ContextualityFeb 14 2019In quantum physics the term `contextual' can be used in more than one way. One usage, here called `Bell contextual' since the idea goes back to Bell, is that if $A$, $B$ and $C$ are three quantum observables, with $A$ compatible (i.e., commuting) with ... More
The maximum advantage of quantum illuminationFeb 14 2019Discriminating between quantum states is a fundamental problem in quantum information protocols. The optimum approach saturates the Helstrom bound, which quantifies the unavoidable error probability of mistaking one state for another. Computing the error ... More
Quantum correlations in optomechanical crystalsFeb 14 2019The field of optomechanics provides us with several examples of quantum photon-phonon interface. In this paper, we theoretically investigate the generation and manipulation of quantum correlations in a microfabricated optomechanical array. We consider ... More
Three-qubit exact Grover within the blind oracular quantum computation schemeFeb 14 2019Here we extend the concept of blind client-server quantum computation, in which a client with limited quantum power controls the execution of a quantum computation on a powerful server, without revealing any details of the computation. Our extension is ... More
Everett's Missing Postulate and the Born RuleFeb 14 2019Everett's Relative State Interpretation (aka Many Worlds Interpretation) has gained increasing interest due to the progress understanding the role of decoherence. In order to fulfill its promise as a realistic description of the physical world, two postulates ... More
Everett's Missing Postulate and the Born RuleFeb 14 2019Feb 15 2019Everett's Relative State Interpretation (aka Many Worlds Interpretation) has gained increasing interest due to the progress understanding the role of decoherence. In order to fulfill its promise as a realistic description of the physical world, two postulates ... More
Local spin manipulation of quantized atomic currentsFeb 14 2019Spin is a fundamental quantum property of matter, and lifting its degeneracy lies at the heart of subtle transport phenomena and future schemes for quantum information processing. Here, we implement a microscopic spin filter for cold fermionic atoms in ... More
Classical Lieb-Robinson bound for estimating equilibration timescales of isolated quantum systemsFeb 14 2019We study equilibration of an isolated quantum system by mapping it onto a network of classical oscillators in Hilbert space. By choosing a suitable basis for this mapping, the degree of locality of the quantum system reflects in the sparseness of the ... More
Quantum chaos in classically non-chaotic systemsFeb 14 2019One of the general goals in the field of quantum chaos is to establish a correspondence between the dynamics of classical chaotic systems and their quantum counterparts. For isolated systems in the absence of decoherence, this correspondence in dynamics ... More
Large-scale multilayer architecture of single-atom arrays with individual addressabilityFeb 14 2019We report on the realization of a novel platform for the creation of large-scale 3D multilayer configurations of planar arrays of individual neutral atoms: a microlens-generated Talbot optical lattice. We demonstrate the trapping and imaging of rubidium ... More
Hydrogen in a cavityFeb 14 2019The system of a proton and an electron in an inert and impenetrable spherical cavity is studied by solving Schr\"{o}dinger equation with the correct boundary conditions. The differential equation of a hydrogen atom in a cavity is derived. The numerical ... More
An exactly solvable quantum-metamaterial type modelFeb 14 2019The key difficulty in the modelling of large quantum coherent structures lies in keeping track of nonlocal, multipoint quantum correlations between their constituent parts. Here we consider a special case of such a system, a fractal quantum metamaterial ... More
Deterministic single ion implantation of rare-earth ions for nanometer resolution colour center generationFeb 14 2019Single dopant atoms or dopant-related defect centers in a solid state matrix provide an attractive platform for quantum simulation of topological states, for quantum computing and communication, due to their potential to realize a scalable architecture ... More
Topologically protected quantization of workFeb 14 2019The transport of a particle in the presence of a potential that changes periodically in space and in time can be characterized by the amount of work needed to shift a particle by a single spatial period of the potential. In general, this amount of work, ... More
Multi-Matrix Post-Processing for Quantum Key DistributionFeb 14 2019Post-processing is a significant step in quantum key distribution(QKD), which is used for correcting the quantum-channel noise errors and distilling identical corrected keys between two distant legitimate parties. Efficient error reconciliation protocol, ... More
Coherent coupling of single molecules to on-chip ring resonatorsFeb 14 2019We report on cryogenic coupling of organic molecules to ring microresonators obtained by looping sub-wavelength waveguides (nanoguides). We discuss fabrication and characterization of the chip-based nanophotonic elements which yield resonator finesse ... More
Efficient passive measurement-device-independent quantum key distributionFeb 14 2019The measurement-device-independent quantum key distribution (MDI-QKD) possesses the highest security among all practical quantum key distribution protocols. However, existing multi-intensity decoy-state methods may cause loopholes when modulating light ... More
Classical zero-knowledge arguments for quantum computationsFeb 14 2019We show that every language in BQP admits a classical-verifier, quantum-prover zero-knowledge argument system which is sound against quantum polynomial-time provers and zero-knowledge for classical (and quantum) polynomial-time verifiers. The protocol ... More
Smart contracts meet quantum cryptographyFeb 14 2019We put forward the idea that classical blockchains and smart contracts are potentially useful primitives not only for classical cryptography, but for quantum cryptography as well. Abstractly, a smart contract is a functionality that allows parties to ... More