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2018-08-23
Bond relaxation, electronic and magnetic behavior of 2D metals structures Y on Li(110) surface
We investigated the bond, electronic and magnetic behavior of adsorption Yttrium atoms on Lithium (110) surface using a combination of Bond-order-length-strength(BOLS) correlation and density-functional theory(DFT). We found that adsorption Y atoms on Li(110) surfaces form two-dimensional (2D) geometric structures of h...
1809.03407v1
2019-01-16
Structure and dielectric properties of Ba$_2$Cu$_x$Y$_{1-x}$TaO$_{6-y}$ double perovskite
In this paper, we reported the effect of Cu doping on the structural and dielectric properties of Ba$_2$Y$_{1-x}$Cu$_x$TaO$_{6-y}$ (0.00 $\leq$ x $\leq$ 0.50) ceramics at room temperature. The Copper for Yttrium substitution reduces the sintering temperature and leads to structural changes in the Ba$_2$YTaO$_6$ rock-sa...
1901.05548v2
2020-03-23
Chemical characterization of dislocation in yttria-stabilized zirconia
This study demonstrates that a space charge layer is formed on dislocation during mechanical deformation at elevated temperature. High density of dislocation lines is generated in bulk single crystalline Y2O3 stabilized ZrO2 (YSZ) by uniaxial compression at elevated temperature. The creation of dislocation is proven wi...
2003.10093v1
2020-04-02
Optical spectra of rare-earth nickelates
Based on the electronic band structure obtained from first principles DFT calculations, the opticalspectra of yttrium and neodymium nickelates are computed. We show that the results are in fairagreement with available experimental data. We clarify the electronic transitions at the origin of thefirst two peaks, highligh...
2004.01100v1
2022-06-25
High cooperativity coupling of rare earth spins with planar superconducting resonator
Interfacing superconducting microwave resonator with rare earth doped crystals presents a promising hybrid quantum system for applications including spin-assisted transducers and memories. The coupling strength between spins of rare earth ions and the microwave photons is characterized by the cooperativity. Here we rep...
2206.12646v1
2022-12-27
Study on the hydrogen behavior in Y and Co doped barium-zirconate
Hydrogen release behavior from mixed-perovskite oxide, yttrium and cobalt doped barium-zirconate, BaZr$_{0.955}$Y$_{0.03}$Co$_{0.015}$O$_{3-a}$ (BZYC) exposed to D$_2$ or D$_2$O atmosphere was studied by thermal desorption spectroscopy (TDS) detecting deuterium gas (D$_2$) and heavy water vapor (D$_2$O) separately. The...
2301.02522v1
2024-02-04
A critical assessment of the dislocation-driven model for superplasticity in yttria tetragonal zirconia polycrystals
In this paper, the origin of the threshold stress in pure 3 mol %-yttria tetragonal zirconia polycrystals (YTZP) is analysed in detail. At this regard, the two explanations reported in literature are discussed thoroughly. One of them invokes dislocation activity as the origin for such quantity, whereas the other one is...
2402.04015v1
2000-06-23
ORFEUS II echelle spectra: On the influence of iron-group line blanketing in the Far-UV spectral range of hot subdwarfs
We present an analysis of the subdwarf O star Feige 67 with a fully metal-line blanketed NLTE model atmosphere based on high-resolution Far-UV (912-2000 A) and Near-UV (2000-3400 A) spectra from new ORFEUS II echelle observations and the IUE final archive. The Far-UV spectra are heavily blanketed by iron and nickel lin...
0006341v1
2002-05-04
Iron abundance in hot hydrogen-deficient central stars and white dwarfs from FUSE, HST, and IUE spectroscopy
We present a first systematic investigation of the iron abundance in very hot (Teff>50,000K) hydrogen-deficient post-AGB stars. Our sample comprises 16 PG1159 stars and four DO white dwarfs. We use recent FUSE observations as well as HST and IUE archival data to perform spectral analyses with line blanketed NLTE model ...
0205058v1
2001-10-18
Suppression of Tc in the (Y0.9Ca0.1)Ba2Cu4-xFexO8 system
In this paper, the effects produced by the iron substitutions in the (Y0.9Ca0.1)Ba2Cu4-xFexO8 system on the superconducting and structural properties are studied. The Rietveld fit of the crystal structure and Mossbauer spectroscopy results of (Y0.9Ca0.1)Ba2Cu4-xFexO8 samples indicate that, the iron atoms occupy the Cu(...
0110388v1
1995-06-30
Structural and Magnetic Properties of Trigonal Iron
First principles calculations of the electronic structure of trigonal iron were performed using density function theory. The results are used to predict lattice spacings, magnetic moments and elastic properties; these are in good agreement with experiment for both the bcc and fcc structures. We find however, that in ex...
9506009v1
2007-12-05
Vertical stratification of iron abundance in atmospheres of blue horizontal-branch stars
The observed slow rotation and abundance peculiarities of certain blue horizontal branch (BHB) stars suggests that atomic diffusion can be important in their stellar atmospheres and can lead to vertical abundance stratification of chemical species in the atmosphere. To verify this hypothesis, we have undertaken an abun...
0712.0809v1
2009-09-03
A Mechanism for the Oxygen and Iron Bimodal Radial Distribution Formation in the Disc of our Galaxy
Recently it has been proposed that there are two types of SN Ia progenitors -- short-lived and long-lived. On the basis of this idea, we develope a theory of a unified mechanism for the formation of the bimodal radial distribution of iron and oxygen in the Galactic disc. The underlying cause for the formation of the fi...
0909.0626v1
2011-03-23
Magnetic Frustration and Iron-Vacancy Ordering in Iron-Chalcogenide
We show that the magnetic and vacancy orders in the 122 $(A_{1-y}Fe_{2-x}Se_2)$ iron-chalcogenides can be naturally derived from the $J_1-J_2-J_3$ model with $J_1$ being the ferromagnetic (FM) nearest neighbor exchange coupling and $J_{2}, J_3$ being the antiferromagnetic (AFM) next and third nearest neighbor ones resp...
1103.4599v2
2011-09-01
Iron and nickel diffusion in subdwarf B stars
Pulsations in subdwarf B stars are attributed to radiative levitation of iron-group elements in the stellar envelope. Until now, only iron diffusion is accounted for in stellar models used for sdB seismology. However, nickel has also been suggested as a contributor to the opacity bump that drives the pulsation modes. S...
1109.0121v1
2012-06-20
Mössbauer study of the '11' iron-based superconductors parent compound Fe(1+x)Te
57Fe Moessbauer spectroscopy was applied to investigate the superconductor parent compound Fe(1+x)Te for x=0.06, 0.10, 0.14, 0.18 within the temperature range 4.2 K - 300 K. A spin density wave (SDW) within the iron atoms occupying regular tetrahedral sites was observed with the square root of the mean square amplitude...
1206.4439v1
2013-02-20
Absence of strong magnetic fluctuations in the iron phosphide superconductors LaFePO and Sr2ScO3FeP
We report neutron inelastic scattering measurements on polycrystalline LaFePO and Sr2ScO3FeP, two members of the iron phosphide families of superconductors. No evidence is found for any magnetic fluctuations in the spectrum of either material in the energy and wavevector ranges probed. Special attention is paid to the ...
1302.5057v2
2013-04-23
Theoretical study of solid iron nanocrystal movement inside a carbon nanotube
We use a first-principles based kinetic Monte Carlo simulation to study the movement of a solid iron nanocrystal inside a carbon nanotube driven by the electrical current. The origin of the iron nanocrystal movement is the electromigration force. Even though the iron nanocrystal appears to be moving as a whole, we find...
1304.6438v1
2014-04-14
Structure and composition of the superconducting phase in alkali iron selenide K$_y$Fe$_{1.6+x}$Se$_2$
We use neutron diffraction to study the temperature evolution of the average structure and local lattice distortions in insulating and superconducting potassium iron selenide K$_y$Fe$_{1.6+x}$Se$_2$. In the high temperature paramagnetic state, both materials have a single phase with crystal structure similar to that of...
1404.3715v1
2014-08-05
Effect of the iron valence in the two types of layers in LiFeO$_2$Fe$_2$Se$_2$
We perform electronic structure calculations for the recently synthesized iron-based superconductor LiFeO$_2$Fe$_2$Se$_2$. In contrast to other iron-based superconductors, this material comprises two different iron atoms in 3$d^5$ and 3$d^6$ configurations. In band theory, both contribute to the low-energy electronic s...
1408.0960v2
2014-12-16
Raman-assisted crystallography reveals end-on peroxide intermediates in a nonheme iron enzyme
Iron-peroxide intermediates are central in the reaction cycle of many iron-containing biomolecules. We trapped iron(III)-(hydro)peroxo species in crystals of superoxide reductase (SOR), a nonheme mononuclear iron enzyme that scavenges superoxide radicals. X-ray diffraction data at 1.95 angstrom resolution and Raman spe...
1412.5040v1
2015-01-05
Reversed anisotropy of the in-plane resistivity in the antiferromagnetic phase of iron tellurides
We systematically investigated the anisotropic in-plane resistivity of the iron telluride including three kinds of impurity atoms: excess Fe, Se substituted for Te, and Cu substituted for Fe. Sizable resistivity anisotropy was found in the magneto-structurally ordered phase whereas the sign is opposite ($\rho_a$ $>$ $\...
1501.00774v1
2015-03-24
Iron spin crossover and its influence on post-perovskite transitions in MgSiO$_3$ and MgGeO$_3$
MgGeO$_3$-perovskite is known to be a low-pressure analog of MgSiO$_3$-perovskite in many respects, but especially in regard to the post-perovskite transition. As such, investigation of spin state changes in Fe-bearing MgGeO$_3$ might help to clarify some aspects of this type of state change in Fe-bearing MgSiO$_3$. Us...
1503.07194v1
2015-05-20
An equatorial ultra iron-poor star identified in BOSS
We report the discovery of SDSS J131326.89-001941.4, an ultra iron-poor red giant star ([Fe/H] ~ -4.3) with a very high carbon abundance ([C/Fe]~ +2.5). This object is the fifth star in this rare class, and the combination of a fairly low effective temperature (Teff ~ 5300 K), which enhances line absorption, with its b...
1505.05555v1
2015-07-21
Pressure-induced Superconductivity in the Iron-based Ladder Material BaFe2S3
All the iron-based superconductors identified to date share a square lattice composed of Fe atoms as a common feature, despite having different crystal structures. In copper-based materials, the superconducting phase emerges not only in square lattice structures but also in ladder structures. Yet iron-based superconduc...
1507.05864v1
2016-10-27
Non-trivial role of interlayer cation states in iron-based superconductors
Unconventional superconductivity in iron pnictides and chalcogenides has been suggested to be controlled by the interplay of low-energy antiferromagnetic spin fluctuations and the particular topology of the Fermi surface in these materials. Based on this premise, one would also expect the large class of isostructural a...
1610.08626v1
2017-01-12
Interplay of iron and rare-earth magnetic order in rare-earth iron pnictide superconductors under magnetic field
The magnetic properties of iron pnictide superconductors with magnetic rare-earth ions under strong magnetic field are investigated based on the cluster self-consistent field method. Starting from an effective Heisenberg model, we present the evolution of magnetic structures on magnetic field in RFeAsO (R=Ce, Pr, Nd, S...
1701.03258v1
2018-09-13
In situ soft x-ray absorption spectroscopic study of Fe/MgO interfaces
Interfacial reaction between iron and MgO has been studied in situ during deposition of iron on MgO surface, using soft x-ray absorption spectroscopy. High sensitivity of the technique which is capable of detecting even a sub monolayer of a given phase, combined with in situ measurements as a function of iron layer thi...
1809.04782v2
2019-01-30
Tidally-Distorted, Iron-Enhanced Exoplanets Closely Orbiting Their Stars
The transiting planet candidate KOI 1843.03 ($0.6 R_\oplus$ radius, 4.245 hour orbital period, $0.46 M_\odot$ host star) has the shortest orbital period of any planet yet discovered. Here we show, using the first three-dimensional interior structure simulations of ultra-short-period tidally distorted rocky exoplanets, ...
1901.10666v2
2019-09-25
Globular Cluster Intrinsic Iron Abundance Spreads: I. Catalog
We present an up-to-date catalog of intrinsic iron abundance spreads in the 55 Milky Way globular clusters for which sufficiently precise spectroscopic measurements are available. Our method combines multiple datasets when possible to improve the statistics, taking into account the fact that different methods and instr...
1909.11731v1
2020-04-07
Electronic correlations and transport in iron at Earth's core conditions
The transport properties of iron under Earth's inner core conditions are essential input for the geophysical modelling but are poorly constrained experimentally. Here we show that the thermal and electrical conductivity of iron at those conditions remains high even if the electron-electron-scattering (EES) is properly ...
2004.03700v2
2021-07-10
Phase separation near the charge neutrality point in FeSe$_{1-x}$Te$_{x}$ crystals with x $<$ 0.15
Our study of FeSe$ _ {1-x}$Te$ _ {x}$ crystals with x $<$ 0.15 shows that the phase separation in these compositions occurs into phases with a different stoichiometry of iron. This phase separation may indicate structural instability of the iron plane in the studied range of compositions. To explain it, we discuss the ...
2107.04793v2
2021-10-27
Synthesis and Characterisation of Iron Oxide Nanoparticles with Tunable Sizes by Hydrothermal Method
The present study investigates the effect of different reaction times on the crystallinity, surface morphology and size of iron oxide nanoparticles. In this synthetic system, aqueous iron (III) nitrate (Fe(NO$_3$)$_3\cdot9$H$_2$O) nonahydrate, provided the iron source and triethylamine was the precipitant and alkaline ...
2110.14774v1
2022-07-29
Structural investigation of Ayurveda Lauha (Iron) Bhasma
In Ayurveda, Lauha (Iron) bhasma is primarily used to cure diseases related with iron deficiency in humans. It is produced from purified raw metallic iron using a combination of multi-step traditional preparation processes described in the Ayurveda literature. Here, we present results of structural investigation perfor...
2207.14615v3
2022-10-18
Impact of Electronic Correlations on High-Pressure Iron: Insights from Time-Dependent Density Functional Theory
We present a comprehensive investigation of the electrical and thermal conductivity of iron under high pressures at ambient temperature, employing the real-time formulation of time-dependent density functional theory (RT-TDDFT). Specifically, we examine the influence of a Hubbard correction (+\textit{U}) to account for...
2210.10132v3
2023-01-16
The fate of water in hydrogen-based iron oxide reduction
Gas-solid reactions are cornerstones of many catalytic and redox processes that will underpin the energy and sustainability transition. The specific case of hydrogen-based iron oxide reduction is the foundation to render the global steel industry fossil-free, an essential target as iron production is the largest single...
2301.06391v1
2024-04-04
The economic consequences of geopolitical fragmentation: Evidence from the Cold War
The Cold War was the defining episode of geopolitical fragmentation in the twentieth century. Trade between East and West across the Iron Curtain (a symbolical and physical barrier dividing Europe into two distinct areas) was restricted, but the severity of these restrictions varied over time. We quantify the trade and...
2404.03508v1
2010-10-25
An extremely peculiar hot subdwarf with a ten-thousand-fold excess of zirconium, yttrium, and strontium
Helium-rich subdwarf B (He-sdB) stars represent a small group of low-mass hot stars with luminosities greater than those of conventional subdwarf B stars, and effective temperatures lower than those of subdwarf O stars. By measuring their surface chemistry, we aim to explore the connection between He-sdB stars, He-rich...
1010.5146v1
2013-02-19
Structure and dynamics in yttrium-based molten rare earth alkali fluorides
The transport properties of molten LiF-YF3 mixtures have been studied by pulsed field gradient nuclear magnetic resonance spectroscopy, potentiometric experiments, and molecular dynamics simulations. The calculated diffusion coefficients and electric conductivities compare very well with the measurements accross a wide...
1302.4563v2
2018-10-24
Radiation Damage and Thermal Recovery of Perovskite Superconductor Yttrium Barium Copper Oxide
High temperature superconducting materials are being considered to generate the magnetic fields required for the confinement of plasma in fusion reactors. The present study aims to assess the microstructural degradation resulting from ion implantation at room temperature under two implantation conditions in Yttrium Bar...
1810.10477v3
2019-01-10
High-cooperativity coupling of a rare-earth spin ensemble to a superconducting resonator using yttrium orthosilicate as a substrate
Yttrium orthosilicate (Y$_2$SiO$_5$, or YSO) has proved to be a convenient host for rare-earth ions used in demonstrations of microwave quantum memories and optical memories with microwave interfaces, and shows promise for coherent microwave--optical conversion owing to its favourable optical and spin properties. The s...
1901.03262v2
2019-04-05
Osmium-Nitrosyl Oxalato-Bridged Lanthanide-Centered Pentanuclear Complexes - Synthesis, Crystal Structures and Magnetic Properties
A series of pentanuclear heterometallic coordination compounds of the general formula (Bu 4 N) 5 [Ln{Os(NO)($\mu$-ox)-Cl 3 } 4 (H 2 O) n ] [Ln = Y (for 2) and Dy (for 3) when n = 0; Ln = Dy (for 3), Tb (for 4), and Gd (for 5) when n = 1] were synthesized by the reaction of the precursor (Bu 4 N) 2 [Os(NO)(ox)-Cl 3 ] (1...
1904.02913v1
2019-09-23
Superconductivity up to 243 K in yttrium hydrides under high pressure
The discovery of high-temperature conventional superconductivity in H3S with a critical temperature of Tc=203 K was followed by the recent record of Tc ~250 K in the face-centered cubic (fcc) lanthanum hydride LaH10 compound. It was realized in a new class of hydrogen-dominated compounds having a clathrate-like crystal...
1909.10482v1
2020-05-23
Hyperfine interaction and coherence time of praseodymium ions at the site 2 in yttrium orthosilicate
Praseodymium (Pr$^{3+}$) ions doped in the site 1 of yttrium orthosilicate (Y$_2$SiO$_5$) has been widely employed as the photonic quantum memory due to their excellent optical coherence and spin coherence. While praseodymium ions occupying the site 2 in Y$_2$SiO$_5$ crystal have better optical coherence as compared wi...
2005.11543v1
2021-03-09
Chemical physics of superconductivity in layered yttrium carbide halides from first principles
We perform a thorough first-principles study on superconductivity in yttrium carbide halide Y$_2$$X_2$C$_2$ ($X$=Cl, Br, I) whose maximum transition temperature ($T_{\rm c}$) amounts to $\sim$10 K. A detailed analysis on the optimized crystal structures reveals that the Y$_2$C$_2$ blocks are compressed uniaxially upon ...
2103.05312v1
2022-04-05
Potential high-$T_{c}$ superconductivity in YCeH$_{x}$ and LaCeH$_{x}$ under pressure
Lanthanum, yttrium, and cerium hydrides are the three most well-known superconducting binary hydrides (La-H, Y-H, and Ce-H systems), which have gained great attention in both theoretical and experimental studies. Recent studies have shown that ternary hydrides composed of lanthanum and yttrium can achieve high supercon...
2204.01921v2
2022-06-29
Optical properties of oxygen-containing yttrium hydride thin films during and after the deposition
The synthesis of the photochromic YHO films is based on the oxidation of deposited yttrium hydride in ambient conditions. The actual state of the films during the deposition process, which is influenced by the deposition pressure and the oxidation caused by the residual gases, is not completely known. We report on the ...
2206.14644v1
2023-07-25
Computational design of new superconducting materials and their targeted experimental synthesis
In the last six years (2015-2021), many superconducting hydrides with critical temperatures $\textit{T}$$_C$ of up to 253 K, a record for today, have been discovered. Now, a special field of hydride superconductivity at ultrahigh pressures has developed. For the most part, the properties of superhydrides are well descr...
2307.13313v1
2023-08-08
ExoMol line lists -- LIII: Empirical Rovibronic spectra of Yttrium Oxide (YO)
Empirical line lists for the open shell molecule $^{89}$Y$^{16}$O (yttrium oxide) and its isotopologues are presented. The line lists cover the 6 lowest electronic states: $X {}^{2}\Sigma^{+}$, $A {}^{2}\Pi$, $A' {}^{2}\Delta$, $B {}^{2}\Sigma^{+}$, $C {}^{2}\Pi$ and $D {}^{2}\Sigma^{+}$ up to 60000 cm$^{-1}$ ($<0.167$...
2308.04173v3
2001-08-01
Conformal lattice of magnetic bubble domains in garnet film
We report experimental observations of magnetic bubble domain arrays with no apparent translational symmetry. Additionally the results of comparative numerical studies are discussed. Our goal is to present experimental evidence for natural occurence of conformal structures.
0108009v1
2002-10-13
Enhanced magnetocaloric effect in frustrated magnets
The magnetothermodynamics of strongly frustrated classical Heisenberg antiferromagnets on kagome, garnet, and pyrochlore lattices is examined. The field induced adiabatic temperature change (dT/dH)_S is significantly larger for such systems compared to ordinary non-frustrated magnets and also exceeds the cooling rate o...
0210288v1
2003-12-24
Subatomic movements of a domain wall in the Peierls potential
Movements of individual domain walls in a ferromagnetic garnet were studied with angstrom resolution. The measurements reveal that domain walls can be locked between adjacent crystallographic planes and propagate by distinct steps matching the lattice periodicity. Domain walls are found to be weakly mobile within valle...
0312631v1
2006-03-27
Modeling transient absorption and thermal conductivity in a simple nanofluid
Molecular dynamics simulations are used to simulate the thermal properties of a model fluid containing nanoparticles (nanofluid). By modelling transient absorption experiments, we show that they provide a reliable determination of interfacial resistance between the particle and the fluid. The flexibility of molecular s...
0603704v1
2003-06-16
Energy levels and lifetimes of Nd IV, Pm IV, Sm IV, and Eu IV
To address the shortage of experimental data for electron spectra of triply-ionized rare earth elements we have calculated energy levels and lifetimes of 4f{n+1} and 4f{n}5d configurations of Nd IV (n=2), Pm IV (n=3), Sm IV (n=4), and Eu IV (n=5) using Hartree-Fock and configuration interaction methods. To control the ...
0306141v1
2002-06-17
Energy levels and lifetimes of Gd IV and enhancement of the electron dipole moment
We have calculated energy levels and lifetimes of 4f7 and 4f6 5d configurations of Gd IV using Hartree-Fock and configuration interaction methods. This allows us to reduce significantly the uncertainty of the theoretical determination of the electron electric dipole moment (EDM) enhancement factor in this ion and, corr...
0206047v1
1995-11-28
A Supersymmetric Treatment of a Particle Subjected to a Ring-shaped Potential
The ring-shaped Hartmann potential $V = \eta \sigma^{2} \epsilon_{0} \left( \frac{2 a_{0}}{r} - \frac{\eta a_{0}^{2}}{r^{2} sin^{2} \theta} \right)$ was introduced in quantum chemistry to describe ring-shaped molecules like benzene. In this article, fundamental concepts of supersymmetric quantum mechanics (SUSYQM) are ...
9511040v1
2003-05-12
Comment on Repulsive Casimir Forces
A recent theoretical calculation shows that the Casimir force between two parallel plates can be repulsive for plates with nontrivial magnetic properties (O. Kenneth et al., Phys. Rev. Lett. 89, 033001 (2002)). According to the authors, the effect may be observed with known materials, such as ferrites and garnets, and ...
0305065v1
2004-10-31
A physical basis for the phase in Feynman path integration
In the path integral formulation of quantum mechanics, the phase factor Exp[iS(x[t])] is associated with every path x[t]. Summing this factor over all paths yields Feynman's propagator as a sum-over-paths. In the original formulation, the complex phase was a mathematical device invoked to extract wave behaviour in a pa...
0411005v1
2008-04-10
Density Matrix Renormalization Group Lagrangians
We introduce a Lagrangian formulation of the Density Matrix Renormalization Group (DMRG). We present Lagrangians which when minimised yield the optimal DMRG wavefunction in a variational sense, both within the general matrix product ansatz, as well as within the canonical form of the matrix product that is constructed ...
0804.1755v1
2008-10-27
Macroscopic signature of protected spins in a dense frustrated magnet
The inability of systems of interacting objects to satisfy all constraints simultaneously leads to frustration. A particularly important consequence of frustration is the ability to access certain protected parts of a system without disturbing the others. For magnets such "protectorates" have been inferred from theory ...
0810.4744v1
2009-01-20
Analytic response theory for the density matrix renormalization group
We propose an analytic response theory for the density matrix renormalization group whereby response properties correspond to analytic derivatives of density matrix renormalization group observables with respect to the applied perturbations. Both static and frequency-dependent response theories are formulated and imple...
0901.3166v1
2009-01-22
Perfect Reflection of Chiral Fermions in Gated Graphene Nanoribbons
We describe the results of a theoretical study of transport through gated metallic graphene nanoribbons using a non-equilibrium Green function method. Although analogies with quantum field theory predict perfect transmission of chiral fermions through gated regions in one dimension, we find \emph{perfect reflection} of...
0901.3407v1
2010-12-15
Giant transversal particle diffusion in a longitudinal magnetic ratchet
We study the transversal motion of paramagnetic particles on a uniaxial garnet film, exhibiting a longitudinal ratchet effect in the presence of an oscillating magnetic field. Without the field, the thermal diffusion coefficient obtained by video microscopy is $D_{0}\approx 3\times 10^{-4}$ $\mu m^2/s$. With the field,...
1012.3343v1
2011-03-10
Analytic Time Evolution, Random Phase Approximation, and Green Functions for Matrix Product States
Drawing on similarities in Hartree-Fock theory and the theory of matrix product states (MPS), we explore extensions to time evolution, response theory, and Green functions. We derive analytic equations of motion for MPS from the least action principle, which describe optimal evolution in the small time-step limit. We f...
1103.2155v1
2012-03-24
4f and 5d levels of Ce3+ in D2 eightfold oxygen coordination
The effects on the 4f and 5d levels of Ce3+ of its first coordination shell geometry in Ce-doped oxides with a D2 8-fold site, like garnets, are studied with embedded cluster, wave function based ab initio methods. The only deformations of a CeO8 cube that are found to shift the lowest 4f-5d transition to the red are t...
1203.5391v1
2012-10-19
Magnetization, Magnetic Susceptibility and ESR in Tb3Ga5O12
We report on the measurement of the magnetic susceptibility and of ESR transitions in the garnet substance Tb$_3$Ga$_5$O$_{12}$ (TGG). The results are compared with a calculation in the framework of crystal field theory for the orthorhombic surroundings of the six inequivalent Tb ions of TGG. We also present a calculat...
1210.5350v1
2012-11-06
Deep trapping states in Cerium doped (Lu,Y,Gd)3(Ga,Al)5O12 single crystal scintillators
We study deep trapping states in Ce3+-doped garnet crystals with the composition (Lu,Y,Gd)3(Ga,Al)5O12, recently shown as having remarkably high light yield. We use thermally stimulated luminescence (TSL) technique above room temperature and determine the composition Gd3Ga3Al2O12 as the host showing the lowest concentr...
1211.1256v1
2014-02-14
Nonlinearity management of photonic composites and observation of spatial-modulation instability due to quintic nonlinearity
We present a procedure for nonlinearity management of metal-dielectric composites. Varying the volume fraction occupied by silver nanoparticles suspended in acetone we could cancel the refractive index related to the third-order susceptibility, $\chi_{eff}^{(3)}$, and the nonlinear refraction behavior was due to the fi...
1402.3345v1
2014-02-23
The intermediate and spin-liquid phase of the half-filled honeycomb Hubbard model
We obtain the phase-diagram of the half-filled honeycomb Hubbard model with density matrix embedding theory, to address recent controversy at intermediate couplings. We use clusters from 2-12 sites and lattices at the thermodynamic limit. We identify a paramagnetic insulating state, with possible hexagonal cluster orde...
1402.5622v1
2014-07-03
Origin of the Phonon Hall Effect in Rare-Earth Garnets
The phonon Hall effect has been observed in the paramagnetic insulator, Tb3Gd5O12. A magnetic field applied perpendicularly to a heat current induces a temperature gradient that is perpendicular to both the field and the current. We show that this effect is due to resonant skew scattering of phonons from the crystal fi...
1407.0802v2
2015-02-16
Correct quantum chemistry in a minimal basis from effective Hamiltonians
We describe how to create ab-initio effective Hamiltonians that qualitatively describe correct chemistry even when used with a minimal basis. The Hamiltonians are obtained by folding correlation down from a large parent basis into a small, or minimal, target basis, using the machinery of canonical transformations. We d...
1502.04698v1
2015-02-26
Excited state geometry optimization with the density matrix renormalization group as applied to polyenes
We describe and extend the formalism of state-specific analytic density matrix renormalization group (DMRG) energy gradients, first used by Liu et al (J. Chem. Theor.Comput. 9, 4462 (2013)). We introduce a DMRG wavefunction maximum overlap following technique to facilitate state-specific DMRG excited state optimization...
1502.07731v2
2015-12-31
A time-dependent formulation of multi-reference perturbation theory
We discuss the time-dependent formulation of perturbation theory in the context of the interacting zeroth-order Hamiltonians that appear in multi-reference situations. As an example, we present a time-dependent formulation and implementation of second-order n-electron valence perturbation theory. The resulting t-NEVPT2...
1512.09213v2
2016-02-12
Density matrix embedding theory for interacting electron-phonon systems
We describe the extension of the density matrix embedding theory (DMET) framework to coupled interacting fermion-boson systems. This provides a frequency-independent, entanglement embedding formalism to treat bulk fermion-boson problems. We illustrate the concepts within the context of the one-dimensional Hubbard-Holst...
1602.04195v1
2016-05-16
The degree of commutativity and lamplighter groups
The degree of commutativity of a group $G$ measures the probability of choosing two elements in $G$ which commute. There are many results studying this for finite groups. In [AMV17], this was generalised to infinite groups. In this note, we compute the degree of commutativity for wreath products of the form $\mathbb{Z}...
1605.04829v2
2016-06-03
Difference of Convex Functions Programming Applied to Control with Expert Data
This paper reports applications of Difference of Convex functions (DC) programming to Learning from Demonstrations (LfD) and Reinforcement Learning (RL) with expert data. This is made possible because the norm of the Optimal Bellman Residual (OBR), which is at the heart of many RL and LfD algorithms, is DC. Improvement...
1606.01128v2
2017-01-17
Gaussian-based coupled-cluster theory for the ground state and band structure of solids
We present the results of Gaussian-based ground-state and excited-state equation-of-motion coupled-cluster theory with single and double excitations for three-dimensional solids. We focus on diamond and silicon, which are paradigmatic covalent semiconductors. In addition to ground-state properties (the lattice constant...
1701.04832v1
2017-09-07
The conjugacy ratio of groups
In this paper we introduce and study the conjugacy ratio of a finitely generated group, which is the limit at infinity of the quotient of the conjugacy and standard growth functions. We conjecture that the conjugacy ratio is $0$ for all groups except the virtually abelian ones, and confirm this conjecture for certain r...
1709.02152v1
2017-10-03
Lowering of the complexity of quantum chemistry methods by choice of representation
The complexity of the standard hierarchy of quantum chemistry methods is not invariant to the choice of representation. This work explores how the scaling of common quantum chemistry methods can be reduced using real-space, momentum-space, and time-dependent intermediate representations without introducing approximatio...
1710.01004v1
2017-11-20
Electron paramagnetic resonance g-tensors from state interaction spin-orbit coupling density matrix renormalization group
We present a state interaction spin-orbit coupling method to calculate electron paramagnetic resonance (EPR) $g$-tensors from density matrix renormalization group wavefunctions. We apply the technique to compute $g$-tensors for the \ce{TiF3} and \ce{CuCl4^2-} complexes, a [2Fe-2S] model of the active center of ferredox...
1711.07195v3
2018-03-27
The fate of atomic spin in atomic scattering off surfaces
We explore model electron dynamics of an atom scattering off a surface within the time-dependent complete active space self consistent field (TD-CASSCF) approximation. We focus especially on the scattering of a hydrogen atom and its resulting spin-dynamics starting from an initially spin-polarized state. Our results re...
1803.09895v1
2018-10-08
Comment on "Numerical Evidence Falsifying Finite-Temperature Many-Body Perturbation Theory"
In this comment we address the preprint of Jha and Hirata (arXiv:1809.10316 [physics.chem-ph]) which claims "Numerical Evidence Falsifying Finite-Temperature Many-Body Perturbation Theory." We agree that finite difference differentiation of the exact grand potential is the correct way to verify the terms in the perturb...
1810.03653v2
2019-04-24
Layered optomagnonic structures: Time Floquet scattering-matrix approach
A fully dynamic theoretical approach to layered optomagnonic structures, based on a time Floquet scattering-matrix method, is developed. Its applicability is demonstrated on a simple design of a dual photonic-magnonic cavity, formed by sandwiching a magnetic garnet thin film between two dielectric Bragg mirrors, subjec...
1904.10714v1
2019-05-02
Projected Density Matrix Embedding Theory with Applications to the Two-Dimensional Hubbard Model
Density matrix embedding theory (DMET) is a quantum embedding theory for strongly correlated systems. From a computational perspective, one bottleneck in DMET is the optimization of the correlation potential to achieve self-consistency, especially for heterogeneous systems of large size. We propose a new method, called...
1905.00886v2
2019-07-26
Time-dependent coupled cluster theory on the Keldysh contour for non-equilibrium systems
We leverage the Keldysh formalism to extend our implementation of finite temperature coupled cluster theory [\textit{J. Chem. Theory Comput.} 2018, \textit{14}, 5690-5700] to thermal systems that have been driven out of equilibrium. The resulting Keldysh coupled cluster theory is discussed in detail. We describe the im...
1907.11695v1
2020-01-09
Theoretical Prediction of Magnetic Exchange Coupling Constants from Broken-Symmetry Coupled Cluster Calculations
Exchange coupling constants ($J$) are fundamental to the understanding of spin spectra of magnetic systems. Here we investigate the broken-symmetry (BS) approaches of Noodleman and Yamaguchi in conjunction with coupled cluster (CC) methods to obtain exchange couplings. $J$ values calculated from CC in this fashion conv...
2001.03226v1
2020-03-06
Dynamical Phase Transitions in a 2D Classical Nonequilibrium Model via 2D Tensor Networks
We demonstrate the power of 2D tensor networks for obtaining large deviation functions of dynamical observables in a classical nonequilibrium setting. Using these methods, we analyze the previously unstudied dynamical phase behavior of the fully 2D asymmetric simple exclusion process with biases in both the x and y dir...
2003.03050v2
2022-07-28
Differentiable quantum chemistry with PySCF for molecules and materials at the mean-field level and beyond
We introduce an extension to the PySCF package which makes it automatically differentiable. The implementation strategy is discussed, and example applications are presented to demonstrate the automatic differentiation framework for quantum chemistry methodology development. These include orbital optimization, propertie...
2207.13836v2
2022-11-07
Multi-site Reaction Dynamics Through Multi-fragment Density Matrix Embedding
The practical description of disordered chemical reactions, where reactions involve multiple species at multiple sites, is presently challenge using correlated electronic structure methods. Here we describe the gradient theory of multi-fragment density matrix embedding theory, which potentially provides a minimal compu...
2211.03728v1
2023-06-28
Fast classical simulation of evidence for the utility of quantum computing before fault tolerance
We show that a classical algorithm based on sparse Pauli dynamics can efficiently simulate quantum circuits studied in a recent experiment on 127 qubits of IBM's Eagle processor [Nature 618, 500 (2023)]. Our classical simulations on a single core of a laptop are orders of magnitude faster than the reported walltime of ...
2306.16372v1
2023-08-24
Non-reciprocal coherent all-optical switching between magnetic multi-states
We present experimental and computational findings of the laser-induced non-reciprocal motion of magnetization during ultrafast photo-magnetic switching in garnets. We found distinct coherent magnetization precession trajectories and switching times between four magnetization states, depending on both directions of the...
2308.12771v1
2016-10-04
Planck's Dusty GEMS. II. Extended [CII] emission and absorption in the Garnet at z=3.4 seen with ALMA
We present spatially resolved ALMA [CII] observations of the bright (flux density S=400 mJy at 350 microns), gravitationally lensed, starburst galaxy PLCK G045.1+61.1 at z=3.427, the "Garnet". This source is part of our set of "Planck's Dusty GEMS", discovered with the Planck's all-sky survey. Two emission-line clouds ...
1610.01169v1
2017-03-09
Magnon mode selective spin transport in compensated ferrimagnets
We investigate the generation of magnonic thermal spin currents and their mode selective spin transport across interfaces in insulating, compensated ferrimagnet/normal metal bilayer systems. The spin Seebeck effect signal exhibits a non-monotonic temperature dependence with two sign changes of the detected voltage sign...
1703.03218v2
2017-10-13
Relieving the frustration through Mn$^{3+}$ substitution in Holmium Gallium Garnet
We present a study on the impact of Mn$^{3+}$ substitution in the geometrically frustrated Ising garnet Ho$_3$Ga$_5$O$_{12}$ using bulk magnetic measurements and low temperature powder neutron diffraction. We find that the transition temperature, $T_N$ = 5.8 K, for Ho$_3$MnGa$_4$O$_{12}$ is raised by almost 20 when com...
1710.05083v1
2018-11-27
GarNet: A Two-Stream Network for Fast and Accurate 3D Cloth Draping
While Physics-Based Simulation (PBS) can accurately drape a 3D garment on a 3D body, it remains too costly for real-time applications, such as virtual try-on. By contrast, inference in a deep network, requiring a single forward pass, is much faster. Taking advantage of this, we propose a novel architecture to fit a 3D ...
1811.10983v3
2021-03-17
Ionic conductivity optimization of composite polymer electrolytes through filler particle chemical modification
The addition of filler particles to polymer electrolytes is known to increment their ionic conductivity (IC). A detailed understanding of how the interactions between the constituent materials are responsible for the enhancement, remains to be developed. A significant contribution is ascribed to an increment of the pol...
2103.09887v1
2021-04-30
A numerical exploration of signal detector arrangement in a spin-wave reservoir computing device
This paper studies numerically how the signal detector arrangement influences the performance of reservoir computing using spin waves excited in a ferrimagnetic garnet film. This investigation is essentially important since the input information is not only conveyed but also transformed by the spin waves into high-dime...
2104.14915v1
2021-08-30
Bright and dark states of two distant macrospins strongly coupled by phonons
We study the collective dynamics of two distant magnets coherently coupled by acoustic phonons that are transmitted through an intercalated crystal. By tuning the ferromagnetic resonances of the two magnets to an acoustic resonance of the crystal, we control a coherent three levels system. We show that the parity of th...
2108.13272v2
2022-02-06
Enhancing Perpendicular Magnetic Anisotropy in Garnet Ferrimagnet by Interfacing with Few-Layer WTe2
Engineering magnetic anisotropy in a ferro- or ferrimagnetic (FM) thin film is crucial in spintronic device. One way to modify the magnetic anisotropy is through the surface of the FM thin film. Here, we report the emergence of a perpendicular magnetic anisotropy (PMA) induced by interfacial interactions in a heterostr...
2202.02834v1
2022-06-23
An Investigation into the Kinetics of $Li^+$ Ion Migration in Garnet-Type Solid State Electrolyte: $Li_7La_3Zr_2O_{12}$
An all solid-state thin film lithium ion battery has been touted the holy grail for energy storage technology ever since the inception of the first one in 1986 by Keiichi Kanehori. Solid-state batteries provide the distinct advantage of outperforming current technology by having a simpler composition, being easier and ...
2206.11435v1