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Full-Text Articles in Physics

Competing Magnetic Interactions In The Antiferromagnetic Topological Insulator Mnbi2te4, Bing Li, J.-Q. Yan, D. Pajerowski, Elijah Gordon, Ana-Marija Nedic, Y. Sizyuk, Liqin Ke, Peter P. Orth, David Vaknin, Robert J. Mcqueeney Apr 2020

Competing Magnetic Interactions In The Antiferromagnetic Topological Insulator Mnbi2te4, Bing Li, J.-Q. Yan, D. Pajerowski, Elijah Gordon, Ana-Marija Nedic, Y. Sizyuk, Liqin Ke, Peter P. Orth, David Vaknin, Robert J. Mcqueeney

Physics and Astronomy Publications

The antiferromagnetic (AFM) compound MnBi2Te4 is suggested to be the first realization of an AFM topological insulator. We report on inelastic neutron scattering studies of the magnetic interactions in MnBi2Te4 that possess ferromagnetic triangular layers with AFM interlayer coupling. The spin waves display a large spin gap and pairwise exchange interactions within the triangular layer are long ranged and frustrated by large next-nearest neighbor AFM exchange. The degree of frustration suggests proximity to a variety of magnetic phases, potentially including skyrmion phases, which could be accessed in chemically tuned compounds or upon the application of symmetry-breaking fields.


Manipulating Magnetism In The Topological Semimetal Eucd2as2, Na Hyun Jo, Brinda Kuthanazhi, Yun Wu, Erik I. Timmons, Tae-Hoon Kim, Lin Zhou, Lin-Lin Wang, Benjamin G. Ueland, Andriy Palasyuk, Dominic H. Ryan, Robert J. Mcqueeney, Kyungchan Lee, Benjamin Schrunk, Anton A. Burkov, Ruslan Prozorov, Sergey L. Bud’Ko, Adam Kaminski, Paul C. Canfield Apr 2020

Manipulating Magnetism In The Topological Semimetal Eucd2as2, Na Hyun Jo, Brinda Kuthanazhi, Yun Wu, Erik I. Timmons, Tae-Hoon Kim, Lin Zhou, Lin-Lin Wang, Benjamin G. Ueland, Andriy Palasyuk, Dominic H. Ryan, Robert J. Mcqueeney, Kyungchan Lee, Benjamin Schrunk, Anton A. Burkov, Ruslan Prozorov, Sergey L. Bud’Ko, Adam Kaminski, Paul C. Canfield

Physics and Astronomy Publications

EuCd2As2 is a magnetic semimetal that has the potential of manifesting nontrivial electronic states, depending on its low temperature magnetic ordering. Here, we report the successful synthesis of single crystals of EuCd2As2 that order ferromagnetically or antiferromagnetically depending on the level of band filling, thus allowing for the use of magnetism to tune the topological properties within the same host. We explored their physical properties via magnetization, electrical transport, heat capacity, and angle-resolved photoemission spectroscopy measurements and conclude that EuCd2As2 is an excellent, tunable system for exploring the interplay of magnetic ordering and topology.


Competing Pairing Interactions Responsible For The Large Upper Critical Field In A Stoichiometric Iron-Based Superconductor Cakfe4as4, Matthew Bristow, William Knafo, Pascal Reiss, William R. Meier, Paul C. Canfield, Stephen J. Blundell, Amalia I. Coldea Apr 2020

Competing Pairing Interactions Responsible For The Large Upper Critical Field In A Stoichiometric Iron-Based Superconductor Cakfe4as4, Matthew Bristow, William Knafo, Pascal Reiss, William R. Meier, Paul C. Canfield, Stephen J. Blundell, Amalia I. Coldea

Physics and Astronomy Publications

The upper critical field of multiband superconductors is an important quantity that can reveal details about the nature of the superconducting pairing. Here we experimentally map out the complete upper-critical-field phase diagram of a stoichiometric superconductor, CaKFe4As4, up to 90T for different orientations of the magnetic field and at temperatures down to 4.2K. The upper critical fields are extremely large, reaching values close to ∼3Tc at the lowest temperature, and the anisotropy decreases dramatically with temperature, leading to essentially isotropic superconductivity at 4.2K. We find that the temperature dependence of the upper critical field can be well described ...


Exceedingly Small Moment Itinerant Ferromagnetism Of Single Crystalline La5co2ge3, Scott M. Saunders, Li Xiang, Rustem Khasanov, Tai Kong, Qisheng Lin, Sergey L. Bud’Ko, Paul C. Canfield Jan 2020

Exceedingly Small Moment Itinerant Ferromagnetism Of Single Crystalline La5co2ge3, Scott M. Saunders, Li Xiang, Rustem Khasanov, Tai Kong, Qisheng Lin, Sergey L. Bud’Ko, Paul C. Canfield

Physics and Astronomy Publications

Single crystals of monoclinic La5Co2Ge3 were grown using a self-flux method and were characterized by room-temperature powder X-ray diffraction, anisotropic temperature and field dependent magnetization, temperature dependent resistivity, specific heat, and muon spin rotation. La5Co2Ge3 has a Curie temperature (TC) of 3.8~K and clear signatures of ferromagnetism in magnetization and μSR data, as well as a clear loss of spin disorder scattering in resistivity data and a sharp specific heat anomaly. The magnetism associated with La5Co2Ge3 is itinerant, has a change in the entropy at TC of ≃0.05 R ln2 per mol-Co, and has a low-field saturated ...


Magnetoelastoresistance In Wte2: Exploring Electronic Structure And Extremely Large Magnetoresistance Under Strain, Na Hyun Jo, Lin-Lin Wang, Peter P. Orth, Sergey L. Bud’Ko, Paul C. Canfield Dec 2019

Magnetoelastoresistance In Wte2: Exploring Electronic Structure And Extremely Large Magnetoresistance Under Strain, Na Hyun Jo, Lin-Lin Wang, Peter P. Orth, Sergey L. Bud’Ko, Paul C. Canfield

Physics and Astronomy Publications

Strain describes the deformation of a material as a result of applied stress. It has been widely employed to probe transport properties of materials, ranging from semiconductors to correlated materials. In order to understand, and eventually control, transport behavior under strain, it is important to quantify the effects of strain on the electronic bandstructure, carrier density, and mobility. Here, we demonstrate that much information can be obtained by exploring magnetoelastoresistance (MER), which refers to magnetic field-driven changes of the elastoresistance. We use this powerful approach to study the combined effect of strain and magnetic fields on the semimetallic transition metal ...


Bulk Superconductivity And Role Of Fluctuations In The Iron-Based Superconductor Fese At High Pressures, Elena Gati, Anna E. Böhmer, Sergey L. Bud’Ko, Paul C. Canfield Oct 2019

Bulk Superconductivity And Role Of Fluctuations In The Iron-Based Superconductor Fese At High Pressures, Elena Gati, Anna E. Böhmer, Sergey L. Bud’Ko, Paul C. Canfield

Physics and Astronomy Publications

The iron-based superconductor FeSe offers a unique possibility to study the interplay of superconductivity with purely nematic as well magnetic-nematic order by pressure (p) tuning. By measuring specific heat under p up to 2.36 GPa, we study the multiple phases in FeSe using a thermodynamic probe. We conclude that superconductivity is bulk across the entire p range and competes with magnetism. In addition, whenever magnetism is present, fluctuations exist over a wide temperature range above both the bulk superconducting and the magnetic transitions. Whereas the magnetic fluctuations are likely temporal, the superconducting fluctuations may be either temporal or spatial ...


Helical Magnetic Ordering In Sr(Co1-Xnix)(2)As-2, John M. Wilde, Andreas Kreyssig, David Vaknin, Nediadath S. Sangeetha, Bing Li, W. Tian, Peter P. Orth, David C. Johnston, Benjamin G. Ueland, Robert J. Mcqueeney Oct 2019

Helical Magnetic Ordering In Sr(Co1-Xnix)(2)As-2, John M. Wilde, Andreas Kreyssig, David Vaknin, Nediadath S. Sangeetha, Bing Li, W. Tian, Peter P. Orth, David C. Johnston, Benjamin G. Ueland, Robert J. Mcqueeney

Physics and Astronomy Publications

SrCo2As2 is a peculiar itinerant magnetic system that does not order magnetically, but inelastic neutron-scattering experiments observe the same stripe-type antiferromagnetic (AF) fluctuations found in many of the Fe-based superconductors along with evidence of magnetic frustration. Here we present results from neutron diffraction measurements on single crystals of Sr(Co1-xNix)(2)As-2 that show the development of long-range AF order with Ni doping. However, the AF order is not stripe type. Rather, the magnetic structure consists of ferromagnetically aligned (FM) layers (with moments laying in the layer) that are AF arranged along c with an incommensurate propagation vector of (0 ...


Postquench Gap Dynamics Of Two-Band Superconductors, Tianbai Cui, Michael Schütt, Peter P. Orth, Rafael M. Fernandes Oct 2019

Postquench Gap Dynamics Of Two-Band Superconductors, Tianbai Cui, Michael Schütt, Peter P. Orth, Rafael M. Fernandes

Physics and Astronomy Publications

Recent experimental progress in the fields of cold quantum gases and ultrafast optical spectroscopy of quantum materials allows us to controllably induce and probe nonadiabatic dynamics of superconductors and superfluids. The time evolution of the gap function before relaxation with the lattice is determined by the superposition of coherently evolving individual Cooper pairs within the manifold of the Bardeen-Cooper-Schrieffer (BCS) wave function. While dynamics following an abrupt quench of the pairing interaction strength in the single-band BCS model has been exactly solved due to the integrability of the model, the dynamics of postquench multiband superconductors remain under scrutiny. Here, we ...


Physical Properties Of Rbi2 (R = La, Ce) Under Pressure, Li Xiang, Elena Gati, Kathryn Neilson, Sergey L. Bud’Ko, Paul C. Canfield Sep 2019

Physical Properties Of Rbi2 (R = La, Ce) Under Pressure, Li Xiang, Elena Gati, Kathryn Neilson, Sergey L. Bud’Ko, Paul C. Canfield

Physics and Astronomy Publications

We present a study of electrical transport properties of RBi2 (R=La,Ce) under hydrostatic pressure up to ∼2.5 GPa. These measurements are complemented by thermodynamic measurements of the specific heat on CeBi2 at different pressures up to 2.55 GPa. For CeBi2, we find a moderate increase of the antiferromagnetic transition, TN, from 3.3 K to 4.4 K by pressures up to 2.55 GPa. Notably, resistance measurements for both CeBi2 and LaBi2 show signatures of superconductivity for pressures above ∼1.7 GPa. However, the absence of superconducting features in specific-heat measurements for CeBi2 indicates that ...


Measurement Of Charm And Bottom Production From Semileptonic Hadron Decays In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Yunxiao Zhai, Et Al., Phenix Collaboration May 2019

Measurement Of Charm And Bottom Production From Semileptonic Hadron Decays In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Yunxiao Zhai, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Measurements of the differential production of electrons from open-heavy-flavor hadrons with charm- and bottom-quark content in p+p collisions at √s=200  GeV are presented. The measurements proceed through displaced-vertex analyses of electron tracks from the semileptonic decay of charm and bottom hadrons using the PHENIX silicon-vertex detector. The relative contribution of electrons from bottom decays to inclusive heavy-flavor-electron production is found to be consistent with fixed-order-plus-next-to-leading-log perturbative-QCD calculations within experimental and theoretical uncertainties. These new measurements in p+p collisions provide a precision baseline for comparable forthcoming measurements in A+A collisions.


Measurement Of Two-Particle Correlations With Respect To Second- And Third-Order Event Planes In Au + Au Collisions At √Snn=200 Gev, A. Adare, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Alexey Yu. Semenov, M. Shimomura, Carla Vale, Feng Wei, Et Al., Phenix Collaboration May 2019

Measurement Of Two-Particle Correlations With Respect To Second- And Third-Order Event Planes In Au + Au Collisions At √Snn=200 Gev, A. Adare, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Alexey Yu. Semenov, M. Shimomura, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present measurements of azimuthal correlations of charged hadron pairs in root s(NN) = 200 GeV Au + Au collisions for the trigger and associated particle transverse-momentum ranges of 1 < p(T)(t) < 10 GeV/c and 0.5 < p(T)(a) < 10 GeV/c. After subtraction of an underlying event using a model that includes higher-order azimuthal anisotropy v(2), v(3,) and v(4), the away-side yield of the highest trigger-p(T)(p(T)(t) > 4 GeV/c) correlations is suppressed compared with that of correlations measured in p + p collisions. At the lowest associated particle p(T)(0.5 < p(T)(a) < 1 GeV/c), the away-side shape and yield are modified relative to those in p + p collisions. These observations are consistent with the scenario of radiative-jet energy loss. For the low-p(T) trigger correlations (2 < p(T)(t) < 4 GeV/c), a finite away-side yield exists and we explore the dependence of the shape of the away-side within the context of an underlying-event model. Correlations are also studied differentially versus event-plane angle Psi(2) and Psi(3). The angular correlations show an asymmetry when selecting the sign of the difference between the trigger-particle azimuthal angle and the Psi(2) event plane. This asymmetry and the measured suppression of the pair yield out-of-plane is consistent with a path-length-dependent energy loss. No Psi(3) dependence can be resolved within experimental uncertainties.


Nonperturbative-Transverse-Momentum Broadening In Dihadron Angular Correlations In √Snn = 200 Gev Proton-Nucleus Collisions, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Apr 2019

Nonperturbative-Transverse-Momentum Broadening In Dihadron Angular Correlations In √Snn = 200 Gev Proton-Nucleus Collisions, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX collaboration has measured high-pT dihadron correlations in p+p, p+Al, and p+Au collisions at √sNN=200 GeV. The correlations arise from inter- and intrajet correlations and thus have sensitivity to nonperturbative effects in both the initial and final states. The distributions of pout, the transverse-momentum component of the associated hadron perpendicular to the trigger hadron, are sensitive to initial- and final-state transverse momenta. These distributions are measured multidifferentially as a function of xE, the longitudinal momentum fraction of the associated hadron with respect to the trigger hadron. The near-side pout widths, sensitive to fragmentation transverse momentum ...


Measurements Of Μμ Pairs From Open Heavy Flavor And Drell-Yan In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Apr 2019

Measurements Of Μμ Pairs From Open Heavy Flavor And Drell-Yan In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

PHENIX reports differential cross sections of mu mu pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in p + p collisions at root s = 200 GeV at forward and backward rapidity (1.2 < vertical bar eta vertical bar < 2.2). The mu mu pairs from c (c) over bar, b (b) over bar, and Drell-Yan are separated using a template fit to unlike- and like-sign muon pair spectra in mass and p(T). The azimuthal opening angle correlation between the muons from c (c ) over bar and b (b) over bar decays and the pair-p(T) distributions are compared to distributions generated using PYTHIA and POWHEG models, which both include next-to-leading order processes. The measured distributions for pairs from a are consistent with PYTHIA calculations. The c (c) over bar data present narrower azimuthal correlations and softer p(T) distributions compared to distributions generated from POWHEG. The b (b ) over bar data are well described by both models. The extrapolated total cross section for bottom production is 3.75 +/- 0.24(stat) +/-(0.35)(0.50) (syst) +/- 0.45(global) [mu b], which is consistent with previous measurements at the Relativistic Heavy Ion Collider in the same system at the same collision energy and is approximately a factor of 2 higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantum-chromodynamics calculations.


Creation Of Quark–Gluon Plasma Droplets With Three Distinct Geometries, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Mar 2019

Creation Of Quark–Gluon Plasma Droplets With Three Distinct Geometries, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Experimental studies of the collisions of heavy nuclei at relativistic energies have established the properties of the quark–gluon plasma (QGP), a state of hot, dense nuclear matter in which quarks and gluons are not bound into hadrons 1–4 . In this state, matter behaves as a nearly inviscid fluid 5 that efficiently translates initial spatial anisotropies into correlated momentum anisotropies among the particles produced, creating a common velocity field pattern known as collective flow. In recent years, comparable momentum anisotropies have been measured in small-system proton–proton (p+p) and proton–nucleus (p+A) collisions, despite expectations that the ...


Intertwined Vestigial Order In Quantum Materials: Nematicity And Beyond, Rafael M. Fernandes, Peter P. Orth, Jorg Schmalian Mar 2019

Intertwined Vestigial Order In Quantum Materials: Nematicity And Beyond, Rafael M. Fernandes, Peter P. Orth, Jorg Schmalian

Physics and Astronomy Publications

A hallmark of the phase diagrams of quantum materials is the existence of multiple electronic ordered states, which, in many cases, are not independent competing phases, but instead display a complex intertwinement. In this review, we focus on a particular realization of intertwined orders: a primary phase characterized by a multi-component order parameter and a fluctuation-driven vestigial phase characterized by a composite order parameter. This concept has been widely employed to elucidate nematicity in iron-based and cuprate superconductors. Here we present a group-theoretical framework that extends this notion to a variety of phases, providing a classification of vestigial orders of ...


Multiparticle Azimuthal Correlations For Extracting Event-By-Event Elliptic And Triangular Flow In Au + Au Collisions At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Feb 2019

Multiparticle Azimuthal Correlations For Extracting Event-By-Event Elliptic And Triangular Flow In Au + Au Collisions At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present measurements of elliptic and triangular azimuthal anisotropy of charged particles detected at forward rapidity 1<|η|<3 in Au + Au collisions at √sNN=200 GeV, as a function of centrality. The multiparticle cumulant technique is used to obtain the elliptic flow coefficients v2{2},v2{4},v2{6}, and v2{8}, and triangular flow coefficients v3{2} and v3{4}. Using the small-variance limit, we estimate the mean and variance of the event-by-event v2 distribution from v2{2} and v2{4}. In a complementary analysis, we also use a folding procedure to study the distributions of v2 and v3 directly, extracting both the mean and variance. Implications for initial geometrical fluctuations and their translation into the final-state momentum distributions are discussed.


Enhanced Nematic Fluctuations Near An Antiferromagnetic Mott Insulator And Possible Application To High-Tc Cuprates, Peter P. Orth, Bhilahari Jeevanesa, Rafael M. Fernandes, Jörg Schmalian Jan 2019

Enhanced Nematic Fluctuations Near An Antiferromagnetic Mott Insulator And Possible Application To High-Tc Cuprates, Peter P. Orth, Bhilahari Jeevanesa, Rafael M. Fernandes, Jörg Schmalian

Physics and Astronomy Publications

Motivated by the widespread experimental observations of nematicity in strongly underdoped cuprate superconductors, we investigate the possibility of enhanced nematic fluctuations in the vicinity of a Mott insulator that displays Néel-type antiferromagnetic order. By performing a strong-coupling expansion of an effective model that contains both Cu-d and O-p orbitals on the square lattice, we demonstrate that quadrupolar fluctuations in the p-orbitals inevitably generate a biquadratic coupling between the spins of the d-orbitals. The key point revealed by our classical Monte-Carlo simulations and large-N calculations is that the biquadratic term favors local stripe-like magnetic fluctuations, which ...


Photon Radiation In Hot Nuclear Matter By Means Of Chiral Anomalies, Kirill Tuchin Jan 2019

Photon Radiation In Hot Nuclear Matter By Means Of Chiral Anomalies, Kirill Tuchin

Physics and Astronomy Publications

A new mechanism of photon emission in the quark-gluon plasma is proposed. Photon dispersion relation in the presence of the CP-odd topological regions generated by the chiral anomaly acquires an imaginary mass. It allows photon radiation through the decay q→qγ and annihilation qq¯→γ processes closely related to the chiral Cherenkov radiation. Unlike previous proposals this mechanism does not require an external magnetic field. The differential photon emission rate per unit volume is computed and shown to be comparable to the rate of photon emission in conventional processes.


Beam-Energy And Centrality Dependence Of Direct-Photon Emission From Ultra-Relativistic Heavy-Ion Collisions, A. Adare, Nicole J. Apadula, Sergey Belikov, Paul Constantin, Lei Ding, Alan Dion, Nathan C. Grau, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Jan Rak, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Alexey Yu. Semenov, Abhisek Sen, M. Shimomura, C. L. Silva, S. Skutnik, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Jan 2019

Beam-Energy And Centrality Dependence Of Direct-Photon Emission From Ultra-Relativistic Heavy-Ion Collisions, A. Adare, Nicole J. Apadula, Sergey Belikov, Paul Constantin, Lei Ding, Alan Dion, Nathan C. Grau, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Jan Rak, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Alexey Yu. Semenov, Abhisek Sen, M. Shimomura, C. L. Silva, S. Skutnik, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX collaboration presents first measurements of low-momentum (0.41\,GeV/c) direct-photon yield dNdirγ/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/dη)α with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different, A+A collision systems. At a given beam energy the scaling also holds for high pT (>5\,GeV/c) but when results from different collision energies are compared, an additional sNN ...


Correlations Of Μμ, Eμ, And Ee Pairs In P+P Collisions At S√=200 Gev And Implications For Cc¯ And Bb¯ Production Mechanisms, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Jan 2019

Correlations Of Μμ, Eμ, And Ee Pairs In P+P Collisions At S√=200 Gev And Implications For Cc¯ And Bb¯ Production Mechanisms, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

PHENIX has measured the azimuthal correlations of muon pairs from charm and bottom semi-leptonic decays in p+p collisions at s√=200 GeV, using a novel analysis technique utilizing both unlike- and like-sign muon pairs to separate charm, bottom and Drell-Yan contributions. The dimuon measurements combined with the previous electron-muon and dielectron measurements span a wide range in rapidity, and are well described by PYTHIA Tune A. Through a Bayesian analysis based on PYTHIA Tune A, we show that leading order pair creation is the dominant (76%±1419%) contribution for bb¯ production, whereas the data favor the scenario in which ...


Phenomenal Magneto-Elastoresistance Of Wte2: Strain Engineering Of Electronic And Quantum Transport Properties, Na Hyun Jo, Lin-Lin Wang, Peter P. Orth, Sergey L. Bud’Ko, Paul C. Canfield Jan 2019

Phenomenal Magneto-Elastoresistance Of Wte2: Strain Engineering Of Electronic And Quantum Transport Properties, Na Hyun Jo, Lin-Lin Wang, Peter P. Orth, Sergey L. Bud’Ko, Paul C. Canfield

Physics and Astronomy Publications

Elastoresistance describes the relative change of a material's resistance when strained. It has two major contributions: strain induced geometric and electronic changes. If the geometric factor dominates, like in ordinary metals such as copper, the elastoresistance is positive and rather small, i.e. typically of order 1. In a few materials, however, changes in electronic structure dominate, which gives rise to larger and even negative values, such as (-11) for Bi. Here, we report that the transition metal dichalcogenide (TMDC) WTe2 is a member of the second group, exhibiting a large and non-monotonic elastoresistance that is about (-20) near ...


Chiral Cherenkov And Chiral Transition Radiation In Anisotropic Matter, Kirill Tuchin Dec 2018

Chiral Cherenkov And Chiral Transition Radiation In Anisotropic Matter, Kirill Tuchin

Physics and Astronomy Publications

A significant contribution to the electromagnetic radiation by a fast electric charge moving in anisotropic chiral matter arises from spontaneous photon radiation due to the chiral anomaly. While such a process, also known as the “vacuum Cherenkov radiation,” is forbidden in the QED vacuum, it can occur in chiral matter, where it is more appropriate to call it the “chiral Cherenkov radiation.” Its contribution to the radiation spectrum is of order α2 compared to α3 of the bremsstrahlung. I derive the frequency spectrum and the angular distribution of this radiation in the high energy limit. The quantum effects ...


Radiative Instability Of Quantum Electrodynamics In Chiral Matter, Kirill Tuchin Nov 2018

Radiative Instability Of Quantum Electrodynamics In Chiral Matter, Kirill Tuchin

Physics and Astronomy Publications

Modification of the photon dispersion relation in chiral matter enables 1 -> 2 scattering. As a result, the single fermion and photon states are unstable to photon radiation and pair production respectively. In particular, a fast fermion moving through chiral matter can spontaneously radiate a photon, while a photon can spontaneously radiate a fast fermion and anti-fermion pair. The corresponding spectra are derived in the ultra-relativistic approximation. It is shown that the polarization of the produced and decayed photons is determined by the sign of the chiral conductivity. Impact of a flat thin domain wall on the spectra is computed.


Transition Radiation As A Probe Of The Chiral Anomaly, Xu-Guang Huang, Kirill Tuchin Nov 2018

Transition Radiation As A Probe Of The Chiral Anomaly, Xu-Guang Huang, Kirill Tuchin

Physics and Astronomy Publications

A fast charged particle crossing the boundary between chiral matter and vacuum radiates transition radiation. Its most remarkable features—the resonant behavior at a certain emission angle and the circular polarization of the spectrum—depend on the parameters of the chiral anomaly in a particular material or matter. Chiral transition radiation can be used to investigate the chiral anomaly in such diverse media as the quark-gluon plasma, Weyl semimetals, and axionic dark matter.


Pseudorapidity Dependence Of Particle Production And Elliptic Flow In Asymmetric Nuclear Collisions Of P + Al, P + Au, D + Au, And 3he + Au At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Nov 2018

Pseudorapidity Dependence Of Particle Production And Elliptic Flow In Asymmetric Nuclear Collisions Of P + Al, P + Au, D + Au, And 3he + Au At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Asymmetric nuclear collisions of p+Al, p+Au, d+Au, and 3He+Au at √sNN=200  GeV provide an excellent laboratory for understanding particle production, as well as exploring interactions among these particles after their initial creation in the collision. We present measurements of charged hadron production dNch/dη in all such collision systems over a broad pseudorapidity range and as a function of collision multiplicity. A simple wounded quark model is remarkably successful at describing the full data set. We also measure the elliptic flow v2 over a similarly broad pseudorapidity range. These measurements provide key constraints on models ...


Production Of Π0 And Η Mesons In Cu + Au Collisions At √Snn = 200 Gev, C. Aidala, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration Nov 2018

Production Of Π0 And Η Mesons In Cu + Au Collisions At √Snn = 200 Gev, C. Aidala, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Production of π0 and η mesons has been measured at midrapidity in Cu+Au collisions at √sNN=200 GeV. Measurements were performed in π0(η)→γγ decay channel in the 1(2)−20 GeV/c transverse momentum range. A strong suppression is observed for π0 and η meson production at high transverse momentum in central Cu+Au collisions relative to the p+p results scaled by the number of nucleon-nucleon collisions. In central collisions the suppression is similar to Au+Au with comparable nuclear overlap. The η/π0 ratio measured as a function of transverse momentum is consistent with mT-scaling ...


Giant Electrostatic Modification Of Magnetism Via Electrolyte-Gate-Induced Cluster Percolation In La1−Xsrxcoo3−Δ, Jeff Walter, T. Charlton, H. Ambaye, M. R. Fitzsimmons, Peter P. Orth, R. M. Fernandes, Chris Leighton Nov 2018

Giant Electrostatic Modification Of Magnetism Via Electrolyte-Gate-Induced Cluster Percolation In La1−Xsrxcoo3−Δ, Jeff Walter, T. Charlton, H. Ambaye, M. R. Fitzsimmons, Peter P. Orth, R. M. Fernandes, Chris Leighton

Physics and Astronomy Publications

Electrical control of magnetism is a long-standing goal in science and technology, with the potential to enable a next generation of low-power memory and logic devices. Recently developed electrolyte gating techniques provide a promising route to realization, although the ultimate limits on modulation of magnetic properties remain unknown. Here, guided by a recent theoretical prediction, we demonstrate large enhancement of electrostatic modulation of ferromagnetic order in ion-gel-gated ultrathin films of the perovskite La0.5Sr0.5CoO3−δ by thickness tuning to the brink of percolation. Application of only 3–4 V is then shown capable of inducing a clear percolation transition ...


Low-Momentum Direct-Photon Measurement In Cu + Cu Collisions At √Snn = 200 Gev, A. Adare, Nathan C. Grau, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, M. Shimomura, S. Skutnik, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Nov 2018

Low-Momentum Direct-Photon Measurement In Cu + Cu Collisions At √Snn = 200 Gev, A. Adare, Nathan C. Grau, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, M. Shimomura, S. Skutnik, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We measured direct photons for pT<5GeV/c in minimum bias and 0%–40% most-central events at midrapidity for Cu+Cu collisions at √sNN=200 GeV. The e+e− contribution from quasireal direct virtual photons has been determined as an excess over the known hadronic contributions in the e+e−mass distribution. A clear enhancement of photons over the binary scaled p+p fit is observed for pT<4 GeV/c in Cu+Cu data. The pT spectra are consistent with the Au+Au data covering a similar number of participants. The inverse slopes of the exponential fits to the excess after subtraction of the p+p baseline are 285±53(stat)±57(syst)MeV/c and 333±72(stat)±45(syst)MeV/c for minimum bias and 0%–40% most-central events, respectively. The rapidity density, dN/dy, of photons demonstrates the same power law as a function of dNch/dη observed in Au+Au at the same collision energy.


Measurement Of Φ-Meson Production At Forward Rapidity In P+P Collisions At √S=510 Gev And Its Energy Dependence From √S=200 Gev To 7 Tev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration Nov 2018

Measurement Of Φ-Meson Production At Forward Rapidity In P+P Collisions At √S=510 Gev And Its Energy Dependence From √S=200 Gev To 7 Tev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the differential cross section of phi(1020)-meson production at forward rapidity in p + p collisions at root s = 510 GeV via the dimuon decay channel. The partial cross section in the rapidity and P-T ranges 1.2 < vertical bar y vertical bar < 2.2 and 2 < p(T) < 7 GeV/c is sigma(phi) = [2.28 +/- 0.09(stat) +/- 0.14(syst) +/- 0.27(norm)] x 10(-2) mb. The energy dependence of sigma(phi) (1.2 < vertical bar y vertical bar < 2.2,2 < p(T) < 5 GeV/c) is studied using the PHENIX measurements at root s = 200 and 510 GeV and the Large Hadron Collider measurements atroot s = 2.76 and 7 TeV. The experimental results arc compared to various event generator predictions (PYTHIA6, PYTHIA8, PHOJET, AMPT, EPOS3, and EPOS-LHC).


Driven Dissipative Dynamics And Topology Of Quantum Impurity Systems, Karyn Le Hur, Loïc Henriet, Loïc Herviou, Kirill Plekhanov, Alexandru Petrescu, Tal Goren, Marco Schiro, Christophe Mora, Peter P. Orth Sep 2018

Driven Dissipative Dynamics And Topology Of Quantum Impurity Systems, Karyn Le Hur, Loïc Henriet, Loïc Herviou, Kirill Plekhanov, Alexandru Petrescu, Tal Goren, Marco Schiro, Christophe Mora, Peter P. Orth

Physics and Astronomy Publications

In this review, we provide an introduction to and an overview of some more recent advances in real-time dynamics of quantum impurity models and their realizations in quantum devices. We focus on the Ohmic spin–boson and related models, which describe a single spin-1/2 coupled with an infinite collection of harmonic oscillators. The topics are largely drawn from our efforts over the past years, but we also present a few novel results. In the first part of this review, we begin with a pedagogical introduction to the real-time dynamics of a dissipative spin at both high and low temperatures ...