 No Matching Results

22 Apr 2022 • Journal Article • Journal of Physics A: Mathematical and Theoretical
Tuning quantumclassical correspondence for atomic and molecular systems in a cavity
AbstractWe show that the correspondence between quantum and classical mechanics can be tuned by varying the coupling strength between an atom or a molecule and the modes of a cavity. In the acceleration gauge (AG) representation, the cavitymatter system is described by an eﬀective Hamiltonian, with a nontrivial coupling appearing in the potential, and with renormalized masses
… show more 
15 Apr 2022 • Journal Article • Communications in Mathematical Physics
Entanglement Subvolume Law for 2D FrustrationFree Spin Systems
AbstractLet H be a frustrationfree Hamiltonian describing a 2D grid of qudits with local interactions, a unique ground state, and local spectral gap lower bounded by a positive constant. For any bipartition defined by a vertical cut of length L running from top to bottom of the grid, we prove that the corresponding entanglement entropy of the ground state of H is upper bounded
… show more 
11 Apr 2022 • Preprint • arXiv
Phononinduced modification of quantum criticality
AbstractWe study the effect of acoustic phonons on the quantum phase transition in the O($N$) model. We develop a renormalization group analysis near (3+1) spacetime dimensions and derive the RG equations using an $\epsilon$expansion. Our results indicate that when the number of flavors of the underlying O($N$) model exceeds a critical number $N_c=4$, the quantum transition
… show more 
11 Apr 2022 • Journal Article • SciPost Physics
Proposal for realizing anomalous Floquet insulators via Chern band annihilation
AbstractTwodimensional periodically driven systems can host an unconventional topological phase unattainable for equilibrium systems, termed the Anomalous FloquetAnderson insulator (AFAI). The AFAI features a quasienergy spectrum with chiral edge modes and a fully localized bulk, leading to nonadiabatic but quantized charge pumping. Here, we show how such a Floquet phase
… show more 
6 Apr 2022 • Preprint • arXiv
Towards a controllable SQUID
AbstractJosephson junctions and superconducting quantum interference devices (SQUID) are important electronic elements, which are based on normal conductor sandwiched between two superconductors. These junctions are produced by evaporation techniques, and once they are embedded in an electronic circuit, their properties are fixed. Using SQUIDs as a tunable component requires
… show more 
1 Apr 2022 • Conference Paper • Physics and Simulation of Optoelectronic Devices XXX
Dynamic filtering and modulation properties of tunnelinjection based quantumdot laser devices
AbstractWe show via a combination of material realistic quantumkinetic theory and experimental differential pumpprobe results, that performance issues in tunnelinjection QD lasers are caused by a filtering effect, resulting from the hybridization of different QD shells with the injector quantum well. The real footprint of applicability in optical communication system is the
… show more 
1 Apr 2022 • Journal Article • Semiconductor Science and Technology
High optical gain in InPbased quantumdot material monolithically grown on silicon emitting at telecom wavelengths
AbstractWe describe the fabrication process and properties of an InP based quantum dot laser structure grown on a 5° offcut silicon substrate. Several layers of quantum dot based dislocation filters embedded in GaAs and InP were used to minimize the defect density in the quantum dot active region which comprised eight emitting dot layers. The structure was analyzed using high
… show more 
1 Apr 2022 • Journal Article • Journal of Applied Physics
Lightinduced trap emptying revealed by intensitydependent quantum efficiency of organic solar cells
AbstractRevisiting the intensitydependent quantum efficiency (IDQE) technique in the context of nonfullerene acceptors, we find that at forwardbias conditions, the response exhibits what seems to be anomalous behavior that is not consistent with light excitation induced trap filling. Analysis based on the Shockley–Read–Hall model leads to the conclusion that the contacts
… show more 
31 Mar 2022 • Journal Article • The Journal of Physical Chemistry C
Explanation of the Opposing Shifts in the Absorption Edge and the Optical Resonance in CuFeS_{2} Nanoparticles
AbstractSizedependent change of the electronic band structure is one of the key features of nanoparticles in the quantum confinement region. CuFeS_{2} nanoparticles have a strong absorption feature in the visible region that has, controversially, been described as neither an excitonic transition nor a free carrier plasmon oscillation. Instead, the absorption feature in CuFeS_{2}
… show more 
26 Mar 2022 • Preprint • arXiv
Roomtemperature strong coupling at the nanoscale achieved by inverse design
AbstractRoomtemperature strong coupling between plasmonic nanocavities and monolayer semiconductors is a prominent path towards efficient, integrated lightmatter interactions. However, designing such systems is challenging due to the nontrivial dependence of the strong coupling on various properties of the cavity and emitter, as well as the subwavelength scale of the interaction
… show more 
24 Mar 2022 • Journal Article • Physical Review Letters
Enhanced CooperPair Injection into a Semiconductor Structure by Resonant Tunneling
AbstractWe demonstrate enhanced Andreev reflection in a $\mathrm{Nb}/\mathrm{InGaAs}/\mathrm{InP}$based superconductorsemiconductor hybrid device resulting in increased Cooperpair injection efficiency, achieved by Cooperpair tunneling into a semiconductor quantum well resonant state. We show this enhancement by
… show more 
23 Mar 2022 • Journal Article • Npj Quantum Information
Free electrons can induce entanglement between photons
AbstractEntanglement of photons is a fundamental feature of quantum mechanics, which stands at the core of quantum technologies such as photonic quantum computing, communication, and sensing. An ongoing challenge in all these is finding an efficient and controllable mechanism to entangle photons. Recent experimental developments in electron microscopy enable to control the
… show more 
22 Mar 2022 • Journal Article • The Journal of Chemical Physics
Ultrafast Vibrational Excitation Transfer on Resonant Antenna Lattices Revealed by TwoDimensional Infrared Spectroscopy
AbstractHighquality lattice resonances in arrays of infrared antennas operating in an opencavity regime form polariton states by means of strong coupling to molecular vibrations. We studied polaritons formed by carbonyl stretching modes of (poly)methyl methacrylate on resonant antenna arrays using femtosecond 2DIR spectroscopy. At a normal incidence of excitation light
… show more 
18 Mar 2022 • Conference Paper • APS March Meeting 2022
Canonical phase measurement enabled by quantum feedback control
AbstractIn addition to extracting information, measurements of quantum systems are a resource for enhancing control and precision. They can be used to alter what we are detecting and allow access to new observables. Current hardware can perform nearideal measurements of photon number or field amplitude, the ability to perform an ideal phase measurement is still lacking, even
… show more 
18 Mar 2022 • Conference Paper • APS March Meeting 2022
Observation of intrinsic topological superconductivity in transition metal dichalcogenide
AbstractTopological superconductors may harbor nonAbelian excitation on its boundaries such as Majorana zero mode – an essential ingredient for quantum information processing. Although, Majorana edge mode has been observed in several hybrid heterostructures and epitaxially grown materials, it is yet to be demonstrated in a layered stoichiometric material. This is essential to
… show more 
17 Mar 2022 • Conference Paper • APS March Meeting 2022
Reducing cavityqubit operation times with antisymmetric pulses for bosonic codes
AbstractBosonic encoding is a nascent robust path to quantum computation, allowing error correction already at the hardware level. For an oscillator dispersively coupled to a two level ancilla, the universal control required for computation with any bosonic code was shown to be possible. However, the rate of control of such systems, as realized by Transmon coupled to a longlived
… show more 
16 Mar 2022 • Conference Paper • APS March Meeting 2022
Coherent NonLocal Subspace Dynamics Induced by Zeno Measurements
AbstractWe describe how an entangling operation related to a CPHASE gate may be implemented by drawing on unique features of quantum measurement. The dynamics of a quantum system can be frozen by sufficiently strong monitoring, i.e., by the quantum Zeno effect. We show here that it is possible to combine local unitary operations and Zeno blocking of a single transition within
… show more 
16 Mar 2022 • Conference Paper • APS March Meeting 2022
Effect of acoustic phonons on quantum criticality
AbstractWe study the fate of quantum criticality in a spin system coupled to gapless phonons. In one dimension, a recent study based on renormalization group (RG) analysis and density matrix renormalization group (DMRG) calculations reveals the possibility of the transition to remain secondorder or driven to firstorder, depending on the ratio of velocities of the spins and
… show more 
15 Mar 2022 • Preprint • arXiv
Algorithmic cooling for resolving state preparation and measurement errors in quantum computing
AbstractState preparation and measurement errors are commonly regarded as indistinguishable. The problem of distinguishing state preparation (SPAM) errors from measurement errors is important to the field of characterizing quantum processors. In this work, we propose a method to separately characterize SPAM errors using a novel type of algorithmic cooling protocol called
… show more 
15 Mar 2022 • Conference Paper • APS March Meeting 2022
Critical excitonic mode interacting with phonons in excitonic insulator Ta_{2}Ni(Se_{1−x}S_{x})_{5}
AbstractExcitonic insulator is a quantum coherent phase resulting from formation of a macroscopic population of electronhole pairs. For a semimetal with narrow overlap of the conduction and valence bands, a finite exciton binding energy could lead to excitonic instability. Candidate material Ta2NiSe5 shows a secondorder structural phase transition at Tc=328K, with two mirror
… show more 
13 Mar 2022 • Journal Article • Advanced Science
Edge State Quantum Interference in Twisted Graphitic Interfaces
AbstractZigzag edges in graphitic systems exhibit localized electronic states that drastically affect their properties. Here, roomtemperature charge transport experiments across a single graphitic interface are reported, in which the interlayer current is confined to the contact edges. It is shown that the current exhibits pronounced oscillations of up to ≈40 µA with a dominant
… show more 
11 Mar 2022 • Journal Article • Journal of Physics D: Applied Physics
Encircling exceptional points of Bloch waves: mode conversion and anomalous scattering
AbstractThe normal modes of nonconservative systems coalesce at the socalled exceptional points (EPs) of their spectrum. These degeneracy points are the source of unusual phenomena, some of which are accessed by encircling the points in a suitable space. Here, we encircle the EPs of the transfer matrix of a periodic laminate, using a spatial perturbation in its stiffness. We
… show more 
10 Mar 2022 • Conference Paper • 2022 Optical Fiber Communications Conference and Exhibition (OFC)
1.5µm Indium Phosphidebased Quantum Dot Lasers and Optical Amplifiers
AbstractAn overview will be given on the progress of quantum dot laser materials addressing the telecom C band and their high potential for the application in optical communication systems, where temperature stability of the device performance as well as a narrow linewidth emission plays an important role. Device results of quantum dot lasers and optical amplifiers will be
… show more 
8 Mar 2022 • Journal Article • Physical Review A
Comment on “Nonlinear quantum effects in electromagnetic radiation of a vortex electron”
AbstractThis comment on the paper by Karlovets and PupasovMaksimov [Phys. Rev. A 103, 012214 (2021)] addresses their criticism of the combined experimental and theoretical study by Remez et al. [Phys. Rev. Lett. 123, 060401 (2019)]. We show, by means of simple optical arguments as well as numerical simulations, that the arguments raised by Karlovets and PupasovMaksimov
… show more 
3 Mar 2022 • Journal Article • Physical Review X
Absence of Heating in a Uniform Fermi Gas Created by Periodic Driving
AbstractUltracold atomic gas provides a useful tool to explore manybody physics. One of the recent additions to this experimental toolbox is Floquet engineering, where periodic modulation of the Hamiltonian allows the creation of effective potentials that do not exist otherwise. When subject to external modulations, however, generic interacting manybody systems absorb energy
… show more 
3 Mar 2022 • Preprint • arXiv
Observation of 2D Cherenkov radiation
AbstractFor over 80 years of research, the conventional description of freeelectron radiation phenomena, such as Cherenkov radiation, has remained unchanged: classical threedimensional electromagnetic waves. Interestingly, in reduced dimensionality, the properties of freeelectron radiation are predicted to fundamentally change. Here, we present the first observation of
… show more 
2 Mar 2022 • Preprint • arXiv
Universal transport in periodically driven systems without longlived quasiparticles
AbstractAn intriguing regime of universal charge transport at high entropy density has been proposed for periodically driven interacting onedimensional systems with Bloch bands separated by a large singleparticle band gap. For weak interactions, a simple picture based on welldefined Floquet quasiparticles suggests that the system should host a quasisteady state current that
… show more 
24 Feb 2022 • Journal Article • Physical Review A
Spectroscopy on the electronelectricdipolemoment–sensitive states of ${\mathrm{ThF}}^{+}$
AbstractAn excellent candidate molecule for the measurement of the electron's electric dipole moment (eEDM) is thorium monofluoride ( ${\mathrm{ThF}}^{+}$) because the eEDM–sensitive state, ${}^{3}{\Delta}_{1}$, is the electronic ground state, and thus is immune to
… show more 
21 Feb 2022 • Preprint • arXiv
Interplay of superconductivity and dissipation in quantum Hall edges
AbstractSystems harboring parafermion zeromodes hold promise as platforms for topological quantum computation. Recent experimental work (G\"{u}l et al., arXiv:2009.07836) provided evidence for proximityinduced superconductivity in fractional quantum Hall edges, a prerequisite in proposed realizations of parafermion zeromodes. The main evidence was the observation of a crossed
… show more 
7 Feb 2022 • Journal Article
Light emission by free electrons in photonic timecrystals
AbstractPhotonic timecrystals (PTCs) are spatially homogeneous media whose electromagnetic susceptibility varies periodically in time, causing temporal reflections and refractions for any wave propagating within the medium. The timereflected and timerefracted waves interfere, giving rise to Floquet modes with momentum bands separated by momentum gaps (rather than energy
… show more 
2 Feb 2022 • Journal Article • The Journal of Chemical Physics
Temperature dependence of Fano resonances in CrPS_{4}
AbstractA Fano resonance, as often observed in scattering, absorption, or transmission experiments, arises from quantum interference between a discrete optical transition and a continuous background. Here, we present a temperaturedependent study on Fano resonances observed in photoluminescence from flakes of the layered semiconductor antiferromagnet chromium thiophosphate
… show more 
31 Jan 2022 • Journal Article • Physical Review Research
Correlationenhanced neural networks as interpretable variational quantum states
AbstractVariational methods have proven to be excellent tools to approximate the ground states of complex manybody Hamiltonians. Generic tools such as neural networks are extremely powerful, but their parameters are not necessarily physically motivated. Thus, an efficient parametrization of the wave function can become challenging. In this Letter we introduce a neuralnetworkbased
… show more 
28 Jan 2022 • Preprint • arXiv
Amplified Emission by Atoms and Lasing in Photonic Time Crystals
AbstractPhotonic Time Crystals (PTCs)  dielectric media with their refractive index modulated periodically in time, offer new opportunities in photonics arising from time reflections and momentum bandgaps. Here, we study the emission of light from a radiation source inside a PTC. We solve the general classical and quantum mechanical models of emission in a temporallyvarying
… show more 
28 Jan 2022 • Journal Article • Entropy
Digital Signatures with Quantum Candies
AbstractQuantum candies (qandies) represent a type of pedagogical simple model that describes many concepts from quantum information processing (QIP) intuitively without the need to understand or make use of superpositions and without the need of using complex algebra. One of the topics in quantum cryptography that has gained research attention in recent years is quantum
… show more 
20 Jan 2022 • Journal Article • Nano Futures
Dynamics of lightinduced charge transfer between carbon nanotube and CdSe/CdS core/shell nanocrystals
AbstractThe integration of semiconducting colloidal nanocrystals (NCs) with carbon nanotubes (CNTs) in a single device presents a unique platform that combines optical flexibility with high charge carrying capability. These qualities are desirable in many applications such as photovoltaic cells, photocatalysis, and light sensors. Here, we present hybrid devices that incorporate
… show more 
18 Jan 2022 • Journal Article • Physical Review B
Quantum measurement with recycled photons
AbstractWe study a device composed of an optical interferometer integrated with a ferrimagnetic sphere resonator (FSR). Magnetooptic coupling can be employed in such a device to manipulate entanglement between optical pulses that are injected into the interferometer and the FSR. The device is designed to allow measuring the lifetime of such macroscopic entangled states in the
… show more 
14 Jan 2022 • Journal Article • Physical Review B
Spin purity of the quantum dot confined electron and hole in an external magnetic field
AbstractWe investigate experimentally and theoretically the temporal evolution of the spin of the conduction band electron and that of the valence band heavy hole, both confined in the same semiconductor quantum dot. We use alloptical pulse techniques to perform complete tomographic measurements of the spin as a function of time after its initialization and study the total
… show more 
4 Jan 2022 • Journal Article • Physical Review Letters
Enhanced Coupling of Electron and Nuclear Spins by Quantum Tunneling Resonances
AbstractNoblegas spins feature hourslong coherence times, owing to their great isolation from the environment, and find practical usage in various applications. However, this isolation leads to extremely slow preparation times, relying on weak spin transfer from an electronspin ensemble. Here we propose a controllable mechanism to enhance this transfer rate. We analyze the
… show more 
Jan 2022 • Journal Article • Progress in Quantum Electronics

Jan 2022 • Journal Article • Annalen Der Physik
SpinSpacetime Censorship
AbstractQuantum entanglement and relativistic causality are key concepts in theoretical works seeking to unify quantum mechanics and gravity. In this article, a gedanken experiment that couples the spin to spacetime is proposed, and is then analyzed in the context of quantum information by using different approaches to quantum gravity. Both classical gravity theory and certain
… show more 
23 Dec 2021 • Journal Article • Journal of Statistical Mechanics: Theory and Experiment
Uncertainty relations for mesoscopic coherent light
AbstractThermodynamic uncertainty relations unveil useful connections between fluctuations in thermal systems and entropy production. This work extends these ideas to the disparate field of zero temperature quantum mesoscopic physics where fluctuations are due to coherent effects and entropy production is replaced by a cost function. The cost function arises naturally as a
… show more 
20 Dec 2021 • Preprint • arXiv
Practical Quantum State Tomography for Gibbs states
AbstractQuantum state tomography is an essential tool for the characterization and verification of quantum states. However, as it cannot be directly applied to systems with more than a few qubits, efficient tomography of larger states on midsized quantum devices remains an important challenge in quantum computing. We develop a tomography approach that requires moderate
… show more 
15 Dec 2021 • Journal Article • Physical Review Letters
Towards an Independent Determination of Muon $g2$ from Muonium Spectroscopy
AbstractWe show that muonium spectroscopy in the coming years can reach a precision high enough to determine the anomalous magnetic moment of the muon below one part per million (ppm). Such an independent determination of muon $g2$ would certainly shed light on the $\sim 2\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mathrm{ppm}$ difference currently
… show more 
10 Dec 2021 • Journal Article • Physical Review B
Failed excitonic quantum phase transition in ${\mathrm{Ta}}_{2}\mathrm{Ni}({\mathrm{Se}}_{1x}{\mathrm{S}}_{x}{)}_{5}$
AbstractWe study the electronic phase diagram of the excitonic insulator candidates ${\mathrm{Ta}}_{2}\mathrm{Ni}{\left({\mathrm{Se}}_{1x}{S}_{x}\right)}_{5}$
… show more 
6 Dec 2021 • Conference Paper • 2021 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS)
Interaction of Microwave Coupled Ferrimagnetic Sphere with Figure8 Laser
AbstractCoupling both optical light and microwave with magnetic materials is a pursued area of research recently as it will lead to emerging quantum technologies. Although spin waves in magnetic materials can be strongly coupled to microwave radiation, effective coupling of optical light with spin wave in magnetic system is still a major challenge. We have set up a figure8
… show more 
1 Dec 2021 • Journal Article • Physical Review X
Quantum Nature of Dielectric Laser Accelerators
AbstractDielectric laser accelerators (DLAs) hold great promise for producing economic and compact onchip radiation sources. Onchip DLAs benefit from fabrication capabilities of the silicon industry and from breakthroughs in siliconphotonic nanostructures to enhance the interaction between particles and laser fields. Seemingly unrelated recent advances in the quantum
… show more 
26 Nov 2021 • Conference Paper • 2021 27th International Semiconductor Laser Conference (ISLC)
Quantum coherent revival in a roomtemperature quantumdot optical amplifier: a route towards practical quantum information processing
AbstractThe hallmark quantumoptics phenomenon: quantum coherent revival was demonstrated in roomtemperature quantum dot optical amplifiers. The revival originates from coherent excitation of, and interaction among, homogeneous subgroups within an inhomogeneous ensemble, which play the role of a multi qubits platform for practical quantum information processing.

23 Nov 2021 • Preprint • arXiv
Quantum information and beyondwith quantum candies
AbstractThe field of quantum information is becoming more known to the general public. However, effectively demonstrating the concepts underneath quantum science and technology to the general public can be a challenging job. We investigate, extend, and greatly expand here "quantum candies" (invented by Jacobs), a pedagogical model for intuitively describing some basic concepts
… show more 
15 Nov 2021 • Journal Article • The Journal of Physical Chemistry C
Room Temperature Colloidal Coating of II–VI Nanoplatelets with Quantum Dots
AbstractThe lowtemperature colloidal production of II–VI nanoplatelet heterostructures has stimulated the interest of researchers due to the possible uses of these materials in various optoelectronic devices. Here, we report a roomtemperature coating by CdS or ZnS dots of preprepared CdSe nanoplatelets. The dot coating process made use of a synthesis developed for the formation
… show more 
13 Nov 2021 • Preprint • arXiv
Fock lasers based on deepstrong coupling of light and matter
AbstractLight and matter can now interact in a regime where their coupling is stronger than their bare energies. This deepstrong coupling (DSC) regime of quantum electrodynamics promises to challenge many conventional assumptions about the physics of light and matter. Here, we show how light and matter interactions in this regime give rise to electromagnetic nonlinearities
… show more 
5 Nov 2021 • Journal Article • Physical Review A
Quantum advantage and noise reduction in distributed quantum computing
AbstractDistributed quantum computing can provide substantial noise reduction due to shallower circuits. An experiment illustrates the advantages in the case of a Grover search. This motivates study of the quantum advantage of the distributed version of the Simon and DeutschJozsa algorithms. We show that the distributed Simon algorithm retains the exponential advantage, but
… show more 
25 Oct 2021 • Journal Article • Nature Physics
Evidence of topological boundary modes with topological nodalpoint superconductivity Associated Content
AbstractTopological superconductors are an essential component for topologically protected quantum computation and information processing. Although signatures of topological superconductivity have been reported in heterostructures, material realizations of intrinsic topological superconductors are rather rare. Here we use scanning tunnelling spectroscopy to study the transition
… show more 
20 Oct 2021 • Preprint • arXiv
The mean field approximation and disentanglement
AbstractThe mean field approximation becomes applicable when entanglement is sufficiently weak. We explore a nonlinear term that can be added to the Schrödinger equation without violating unitarity of the time evolution. We find that the added term suppresses entanglement, without affecting the evolution of any product state. The dynamics generated by the modified Schrödinger
… show more 
12 Oct 2021 • Preprint • arXiv
A deterministic source of indistinguishable photons in a cluster state
AbstractMeasurementbased quantum communication relies on the availability of highly entangled multiphoton cluster states. The inbuilt redundancy in the cluster allows communication between remote nodes using repeated local measurements, compensating for photon losses and probabilistic Bellmeasurements. For feasible applications, the cluster generation should be fast
… show more 
7 Oct 2021 • Preprint • arXiv
Generalized FresnelFloquet equations for driven quantum materials
AbstractOptical drives at terahertz and midinfrared frequencies in quantum materials are increasingly used to reveal the nonlinear dynamics of collective modes in correlated manybody systems and their interplay with electromagnetic waves. Recent experiments demonstrated several surprising optical properties of transient states induced by driving, including the appearance of
… show more 
7 Oct 2021 • Journal Article • Npj Computational Materials
Method for assessing atomic sources of flicker noise in superconducting qubits
AbstractFlicker noise causes decoherence in Josephson junctionbased superconducting qubits, thus limiting their practical potential as building blocks for quantum computers. This is due to limited length and complexity of executable algorithms, and increased dependency on errorcorrecting measures. Therefore, identifying and subsiding the atomic sources of flicker noise are
… show more 
4 Oct 2021 • Preprint • arXiv
Mode coupling, bistability, and spectral broadening in buckled nanotube resonators
AbstractBistable mechanical resonators play a significant role in various applications, such as sensors, memory elements, and quantum computing. While carbon nanotube (CNT) based resonators have been widely investigated as promising nano electromechanical devices, a bistable CNT resonator has never been demonstrated. Here, we report a new class of CNT resonators in which
… show more 
30 Sep 2021 • Preprint • arXiv
Illustrating quantum information with quantum candies
AbstractThe field of quantum information is becoming more known to the general public. However, effectively demonstrating the concepts underneath quantum science and technology to the general public can be a challenging job. We investigate, extend, and much expand here "quantum candies" (invented by Jacobs), a pedagogical model for intuitively describing some basic concepts in
… show more 
30 Sep 2021 • Journal Article • Applied Physics Letters
Prospects in xray science emerging from quantum optics and nanomaterials
AbstractThe science of xrays is by now over 125 years old, starting with Wilhelm Röntgen's discovery of xrays in 1895, for which Röntgen was awarded the first Nobel Prize in Physics. Xrays have fundamentally changed the world in areas, including medical imaging, security scanners, industrial inspection, materials development, and drugs spectroscopy. Xray science has been
… show more 
18 Sep 2021 • Quantum Dot Photodetectors
TwoDimensional MaterialBased Quantum Dots for WavelengthSelective, Tunable, and Broadband Photodetector Devices
AbstractThe rise of atomically thin twodimensional (2D) materials brings a revolution in material science and engineering, and encouraged worldwide scientists to integrate desired 2D materials into electrical circuitry by noncovalent interactions. Regardless of some unique properties including superflexibility, broadband absorption and high carrier mobility, the weak optical
… show more 
17 Sep 2021 • Journal Article • New Journal of Physics
Selection rules for breaking selection rules
AbstractFloquet systems often exhibit dynamical symmetries (DS) that govern the timedependent dynamics and result in selection rules. When a DS is broken, selection rule deviations are expected. Typically, information about the symmetrybreaking perturbation/phase and the timedependent dynamics can be extracted from these deviations, hence they are regarded as a background
… show more 
13 Sep 2021 • Journal Article • Applied Physics Letters
Nonvolatile voltagetunable ferroelectricsuperconducting quantum interference memory devices
AbstractSuperconductivity serves as a unique solidstate platform for electron interference at a devicerelevant lengthscale, which is essential for quantum information and sensing technologies. As opposed to semiconducting transistors that are operated by voltage biasing at the nanometer scale, superconductive quantum devices cannot sustain voltage and are operated with magnetic
… show more 
6 Sep 2021 • Journal Article • Nature Communications
Electronic Floquet gyroliquid crystal
AbstractFloquet engineering uses coherent timeperiodic drives to realize designer band structures ondemand, thus yielding a versatile approach for inducing a wide range of exotic quantum manybody phenomena. Here we show how this approach can be used to induce nonequilibrium correlated states with spontaneously broken symmetry in lightly doped semiconductors. In the presence
… show more 
30 Aug 2021 • Journal Article • Molecules
Variational Solutions for Resonances by a FiniteDifference Grid Method
AbstractWe demonstrate that the finite difference grid method (FDM) can be simply modified to satisfy the variational principle and enable calculations of both real and complex poles of the scattering matrix. These complex poles are known as resonances and provide the energies and inverse lifetimes of the system under study (e.g., molecules) in metastable states. This approach
… show more 
26 Aug 2021 • Journal Article • Science
Imprinting the quantum statistics of photons on free electrons
AbstractThe interaction between free electrons and light stands at the base of both classical and quantum physics, with applications in freeelectron acceleration, radiation sources, and electron microscopy. Yet to this day, all experiments involving freeelectron–light interactions are fully explained by describing the light as a classical wave. We observed quantum statistics
… show more 
25 Aug 2021 • Journal Article • Physical Review Letters
SyntheticSpace Photonic Topological Insulators Utilizing Dynamically Invariant Structure
AbstractSyntheticspace topological insulators are topological systems with at least one spatial dimension replaced by a periodic arrangement of modes, in the form of a ladder of energy levels, cavity modes, or some other sequence of modes. Such systems can significantly enrich the physics of topological insulators, in facilitating higher dimensions, nonlocal coupling, and more
… show more 
22 Aug 2021 • Journal Article • Entropy
The Problem of Engines in Statistical Physics
AbstractEngines are open systems that can generate work cyclically at the expense of an external disequilibrium. They are ubiquitous in nature and technology, but the course of mathematical physics over the last 300 years has tended to make their dynamics in time a theoretical blind spot. This has hampered the usefulness of statistical mechanics applied to active systems
… show more 
19 Aug 2021 • Preprint • arXiv
Demonstration of an entangling gate between noninteracting qubits using the Quantum Zeno effect
AbstractThe Zeno effect occurs in quantum systems when a very strong measurement is applied, which can alter the dynamics in nontrivial ways. Despite being dissipative, the dynamics stay coherent within any degenerate subspaces of the measurement. Here we show that such a measurement can turn a singlequbit operation into a two or multiqubit entangling gate, even in a
… show more 
19 Aug 2021 • Preprint • arXiv
Optimal shorttime measurements for Hamiltonian learning
AbstractCharacterizing noisy quantum devices requires methods for learning the underlying quantum Hamiltonian which governs their dynamics. Often, such methods compare measurements to simulations of candidate Hamiltonians, a task which requires exponential computational complexity. Here, we analyze and optimize a method which circumvents this difficulty using measurements of
… show more 
15 Aug 2021 • Preprint • arXiv
On the carrier transport and radiative recombination mechanisms in tunneling injection quantum dot lasers
AbstractWe report temperaturedependent currentvoltage (I  V  T) and output light powervoltage or current (P  V  T) or (P  I  T) characteristics of 1550 nm tunneling injection quantum dot (TI QD) laser diodes. Experimental data is accompanied by physical models that distinguish between different current flow and light emission mechanisms for different applied voltages
… show more 
12 Aug 2021 • Preprint • arXiv
Quantum tomography of entangled spinmultiphoton states
AbstractWe present a novel method for quantum tomography of multiqubit states. We apply the method to spinmultiphoton states, which we produce by periodic excitation of a semiconductor quantumdot confined spin every 1/4 of its coherent precession period. These timed excitations lead to the deterministic generation of strings of entangled photons in a cluster state. We show
… show more 
11 Aug 2021 • Journal Article • Science Advances
Orbital angular momentum multiplication in plasmonic vortex cavities
AbstractOrbital angular momentum of light is a core feature in photonics. Its confinement to surfaces using plasmonics has unlocked many phenomena and potential applications. Here, we introduce the reflection from structural boundaries as a new degree of freedom to generate and control plasmonic orbital angular momentum. We experimentally demonstrate plasmonic vortex cavities
… show more 
5 Aug 2021 • Journal Article • Physical Review Letters
Superradiance and Subradiance due to Quantum Interference of Entangled Free Electrons
AbstractWhen multiple quantum emitters radiate, their emission rate may be enhanced or suppressed due to collective interference in a process known as super or subradiance. Such processes are well known to occur also in light emission from free electrons, known as coherent cathodoluminescence. Unlike atomic systems, free electrons have an unbounded energy spectrum, and, thus
… show more 
30 Jul 2021 • Conference Paper • Microscopy and Microanalysis
Extreme LightMatter Interactions in the Ultrafast Transmission Electron Microscope
AbstractOver the past few years, quantized interactions between coherent free electrons and femtosecond laser pulses have shown intriguing new prospects for lightmatter interactions. The talk will present theory and experiments of free electrons in laserdriven (ultrafast) transmission electron microscopy. Our experiment achieved what is, in many respects, the most powerful
… show more 
20 Jul 2021 • Journal Article • Physical Review D
Experimental observation of accelerationinduced thermality
AbstractWe examine the radiation emitted by highenergy positrons channeled into silicon crystal samples. The positrons are modeled as semiclassical vector currents coupled to an UnruhDeWitt detector to incorporate any local change in the energy of the positron. In the subsequent accelerated QED analysis, we discover a Larmor formula and power spectrum that are both thermalized
… show more 
20 Jul 2021 • Journal Article • Physical Review Research
Roomtemperature coherent revival in an ensemble of quantum dots
Roomtemperature coherent revival in an ensemble of quantum dotsSemiconductor quantum dots (QDs) are nanocrystals with atomlike delta function density of states and discrete energy levels. Advancements in fabrication led to record QD homogeneity and implementation in semiconductor laser structures which exhibit remarkable properties highlighted by ultranarrow spectral emission and temperatureinsensitive operation. An emerging application of such QDs is manipulation of optically induced coherent states of the QDs using ultrashort pulses. The most important of those is a demonstration of the hallmark quantum optics phenomena: collapse and revival of wave functions induced and observed in a QD ensemble in the form of an optical amplifier. The observation of quantum coherent revivals was not observed previously in solids, and in all media it was demonstrated only at cryogenic temperatures. Furthermore, coherently excited discrete homogeneous QD subgroups within an ensemble act as multiple quantum bits, resembling molecules in nuclear magnetic resonance (NMR) and can equally serve for quantum communication, simulation and sensing applications. The room temperature QDs exhibit a record long dephasing time (T2), we envision therefore a host of future compact quantum devices based on high quality QDs which do not require cryogenic cooling.
AbstractWe demonstrate the hallmark concept of periodic collapse and revival of coherence in a roomtemperature ensemble of quantum dots (QDs) in the form of a 1.5mmlong optical amplifier. Femtosecond excitation pulses induce coherent interactions with a number of