Physical Review X

Journal: Physical Review X

Abbreviation

Phys. rev., X

Publisher

American Physical Society

ISSN

2160-3308

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Publications1 - 10 of 140

Operando Imaging of All-Electric Spin Texture Manipulation in Ferroelectric and Multiferroic Rashba Semiconductors
Krempasky, Juraj; Muff, Stefan; Minar, Jan; et al. (2018)
Physical Review X
The control of the electron spin by external means is a key issue for spintronic devices. Using spin- and angle-resolved photoemission spectroscopy (SARPES) with three-dimensional spin detection, we demonstrate operando electrostatic spin manipulation in ferroelectric α−GeTe and multiferroic Ge1−xMnxTe. We demonstrate for the first time electrostatic spin manipulation in Rashba semiconductors due to ferroelectric polarization reversal. Additionally, we are also able to follow the switching pathway in detail. In multiferroic Ge1−xMnxTe operando SARPES reveals switching of the perpendicular spin component due to electric-field-induced magnetization reversal. This provides firm evidence of magnetoelectric coupling which opens up functionality with a multitude of spin-switching paths in which the magnetic and electric order parameters are coupled through ferroelastic relaxation paths. This work thus provides a new type of magnetoelectric switching intertwined with Rashba-Zeeman splitting in a multiferroic system.
Search for supersymmetry in pp collisions at √s=13 TeV with 137 fb−1 in final states with a single lepton using the sum of masses of large-radius jets
CMS Collaboration; Sirunyan, Albert M.; Backhaus, Malte; et al. (2020)
Physical Review X
Results are reported from a search for new physics beyond the standard model in proton-proton collisions in final states with a single lepton; multiple jets, including at least one jet tagged as originating from the hadronization of a bottom quark; and large missing transverse momentum. The search uses a sample of proton-proton collision data at √ s = 13 TeV , corresponding to 137 fb − 1 , recorded by the CMS experiment at the LHC. The signal region is divided into categories characterized by the total number of jets, the number of bottom quark jets, the missing transverse momentum, and the sum of masses of large-radius jets. The observed event yields in the signal regions are consistent with estimates of standard model backgrounds based on event yields in the control regions. The results are interpreted in the context of simplified models of supersymmetry involving gluino pair production in which each gluino decays into a top quark-antiquark pair and a stable, unobserved neutralino, which generates missing transverse momentum in the event. Scenarios with gluino masses up to about 2150 GeV are excluded at 95% confidence level (or more) for neutralino masses up to 700 GeV. The highest excluded neutralino mass is about 1250 GeV, which holds for gluino masses around 1850 GeV.
Quantum Logic Spectroscopy with Ions in Thermal Motion
Kienzler, Daniel; Wan, Y.; Erickson, Stephen D.; et al. (2020)
Physical Review X
A mixed-species geometric phase gate has been proposed for implementing quantum logic spectroscopy on trapped ions, which combines probe and information transfer from the spectroscopy to the logic ion in a single pulse. We experimentally realize this method, show how it can be applied as a technique for identifying transitions in currently intractable atoms or molecules, demonstrate its reduced temperature sensitivity, and observe quantum-enhanced frequency sensitivity when it is applied to multi-ion chains. Potential applications include improved readout of trapped-ion clocks and simplified error syndrome measurements for quantum error correction.
Observation of a Dissipation-Induced Classical to Quantum Transition
Raftery, James; Sadri, Darius; Schmidt, Sebastian; et al. (2014)
Physical Review X
Here, we report the experimental observation of a dynamical quantum phase transition in a strongly interacting open photonic system. The system studied, comprising a Jaynes-Cummings dimer realized on a superconducting circuit platform, exhibits a dissipation-driven localization transition. Signatures of the transition in the homodyne signal and photon number reveal this transition to be from a regime of classical oscillations into a macroscopically self-trapped state manifesting revivals, a fundamentally quantum phenomenon. This experiment also demonstrates a small-scale realization of a new class of quantum simulator, whose well-controlled coherent and dissipative dynamics is suited to the study of quantum many-body phenomena out of equilibrium.
Scaling Behaviour and Beyond Equilibrium in the Hexagonal Manganites
Griffin, Sinéad M.; Lilienblum, Martin; Delaney, Kris T.; et al. (2012)
Physical Review X
We show that the improper ferroelectric phase transition in the multiferroic hexagonal manganites displays appropriate symmetry-breaking characteristics for testing the Kibble-Zurek mechanism originally proposed to describe early-universe phase transitions. We present an analysis of the Kibble-Zurek theory of topological defect formation applied to the hexagonal manganites, discuss the conditions determining the range of cooling rates in which Kibble-Zurek behavior is expected, and show that recent literature data are consistent with our predictions. Finally, we explore experimentally the crossover out of the Kibble-Zurek regime and find a surprising reversal of the scaling behavior.
Accelerating Polaritons with External Electric and Magnetic Fields
Chervy, Thibault; Knüppel, Patrick; Abbaspour, Hadis; et al. (2020)
Physical Review X
It is widely assumed that photons cannot be manipulated using electric or magnetic fields. Even though hybridization of photons with electronic polarization to form exciton-polaritons has paved the way to a number of groundbreaking experiments in semiconductor microcavities, the neutral bosonic nature of these quasiparticles has severely limited their response to external gauge fields. Here, we demonstrate polariton acceleration by external electric and magnetic fields in the presence of nonperturbative coupling between polaritons and itinerant electrons, leading to formation of new quasiparticles termed polaron-polaritons. We identify the generation of electron density gradients by the applied fields to be primarily responsible for inducing a gradient in polariton energy, which in turn leads to acceleration along a direction determined by the applied fields. Remarkably, we also observe that different polarization components of the polaritons can be accelerated in opposite directions when the electrons are in ν=1 integer quantum Hall state.
Realization of a Universal Quantum Gate Set for Itinerant Microwave Photons
Reuer, Kevin; Besse, Jean-Claude; Wernli, Lucien; et al. (2022)
Physical Review X
Large-scale quantum computing will likely employ distributed network architectures in which photons, the fundamental quantum units of light, act as mobile carriers of quantum information to communicate between network nodes. Engineering the necessary interactions between two photons is challenging at optical frequencies but is more readily achievable at microwave frequencies. Here, we experimentally demonstrate an entangling two-qubit gate—a fundamental building block of any quantum algorithm—using controlled interactions between itinerant microwave photons.Our setup makes use of the strong coupling between microwave photons and superconducting circuit devices. We use one device to generate single-photon wave packets acting as flying qubits, which are then funneled to a second superconducting circuit engineered to perform one of two operations on the received qubit. The receiving circuit can absorb, act on, and reemit a qubit (a single-qubit gate) or it can shift the phase of a qubit depending on the state of another (a controlled-phase gate). These operations represent a universal set of quantum gates of microwave-photon qubits.We envision this setup being used to generate larger entanglement among many microwave-photon qubits and finding a wide range of applications in superconducting quantum networks.
Long-Ranged Oppositely Charged Interactions for Designing New Types of Colloidal Clusters
Demirörs, Ahmet; Stiefelhagen, Johan C.P.; Vissers, Teun; et al. (2015)
Physical Review X
Getting control over the valency of colloids is not trivial and has been a long-desired goal for the colloidal domain. Typically, tuning the preferred number of neighbors for colloidal particles requires directional bonding, as in the case of patchy particles, which is difficult to realize experimentally. Here, we demonstrate a general method for creating the colloidal analogs of molecules and other new regular colloidal clusters without using patchiness or complex bonding schemes (e.g., DNA coating) by using a combination of long-ranged attractive and repulsive interactions between oppositely charged particles that also enable regular clusters of particles not all in close contact. We show that, due to the interplay between their attractions and repulsions, oppositely charged particles dispersed in an intermediate dielectric constant (4<ϵ<10) provide a viable approach for the formation of binary colloidal clusters. Tuning the size ratio and interactions of the particles enables control of the type and shape of the resulting regular colloidal clusters. Finally, we present an example of clusters made up of negatively charged large and positively charged small satellite particles, for which the electrostatic properties and interactions can be changed with an electric field. It appears that for sufficiently strong fields the satellite particles can move over the surface of the host particles and polarize the clusters. For even stronger fields, the satellite particles can be completely pulled off, reversing the net charge on the cluster. With computer simulations, we investigate how charged particles distribute on an oppositely charged sphere to minimize their energy and compare the results with the solutions to the well-known Thomson problem. We also use the simulations to explore the dependence of such clusters on Debye screening length κ−1 and the ratio of charges on the particles, showing good agreement with experimental observations.
Optimal Renormalization Group Transformation from Information Theory
Lenggenhager, Patrick M.; Gökmen, Doruk Efe; Ringel, Zohar; et al. (2020)
Physical Review X
Recently, a novel real-space renormalization group (RG) algorithm was introduced. By maximizing an information-theoretic quantity, the real-space mutual information, the algorithm identifies the relevant low-energy degrees of freedom. Motivated by this insight, we investigate the information-theoretic properties of coarse-graining procedures for both translationally invariant and disordered systems. We prove that a perfect real-space mutual information coarse graining does not increase the range of interactions in the renormalized Hamiltonian, and, for disordered systems, it suppresses the generation of correlations in the renormalized disorder distribution, being in this sense optimal. We empirically verify decay of those measures of complexity as a function of information retained by the RG, on the examples of arbitrary coarse grainings of the clean and random Ising chain. The results establish a direct and quantifiable connection between properties of RG viewed as a compression scheme and those of physical objects, i.e., Hamiltonians and disorder distributions. We also study the effect of constraints on the number and type of coarse-grained degrees of freedom on a generic RG procedure.
Primary Thermometry of Propagating Microwaves in the Quantum Regime
Scigliuzzo, Marco; Bengtsson, Andreas; Besse, Jean-Claude; et al. (2020)
Physical Review X
The ability to control and measure the temperature of propagating microwave modes down to very low temperatures is indispensable for quantum information processing and may open opportunities for studies of heat transport at the nanoscale, also in the quantum regime. Here, we propose and experimentally demonstrate primary thermometry of propagating microwaves using a transmon-type superconducting circuit. Our device operates continuously, with a sensitivity down to 4 x 10(-4) photons/root Hz and a bandwidth of 40 MHz. We measure the thermal occupation of the modes of a highly attenuated coaxial cable in a range of 0.001 to 0.4 thermal photons, corresponding to a temperature range from 35 mK to 210 mK at a frequency around 5 GHz. To increase the radiation temperature in a controlled fashion, we either inject calibrated, wideband digital noise, or heat the device and its environment. This thermometry scheme can find applications in benchmarking and characterization of cryogenic microwave setups, temperature measurements in hybrid quantum systems, and quantum thermodynamics.

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Journal: Physical Review X

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