Spin Rotation Research Articles

Unveiling hidden geometric phase of neutron spin rotation in the Bitter-Dubbers experiment

Abstract We propose a novel framework to describe geometric phases in quantum systems under non-adiabatic conditions by introducing the concept of a hidden geometric phase. Conventional geometric phases, such as the Berry phase, rely on adiabatic evolution, limiting their applicability in rapidly changing systems. Here, we remove this constraint by reinterpreting the geometric phase as arising from a dynamically evolving reference basis, independent of the external topological features. The hidden phase is revealed through transitionless quantum control techniques, ensuring pure geometric phase accumulation even in non-adiabatic regimes. Our method offers an exact solution to the neutron spin rotation phase in the Bitter-Dubbers experiment, aligning more closely with experimental data without depending on adiabatic approximations. This unexpected result broadens our understanding of the geometric phase observed in neutron spin rotation beyond the adiabatic conditions that are conventionally required.

Entanglement asymmetry in the critical XXZ spin chain

Abstract We study the explicit breaking of a SU(2) symmetry to a U(1) subgroup employing the entanglement asymmetry, a recently introduced observable that measures how much symmetries are broken in a part of extended quantum systems. We consider as specific model the critical XXZ spin chain, which breaks the SU(2) symmetry of spin rotations except at the isotropic point, and is described by the massless compact boson in the continuum limit. We examine the U(1) subgroup of SU(2) that is broken outside the isotropic point by applying conformal perturbation theory, which we complement with numerical simulations on the lattice. We also analyse the entanglement asymmetry of the full SU(2) group. By relying on very generic scaling arguments, we derive an asymptotic expression for it.

Reviving the Lieb-Schultz-Mattis theorem in open quantum systems.

In closed systems, the celebrated Lieb-Schultz-Mattis (LSM) theorem states that a one-dimensional locally interacting half-integer spin chain with translation and spin rotation symmetries cannot have a non-degenerate gapped ground state. However, the applicability of this theorem is diminished when the system interacts with a bath and loses its energy conservation. In this letter, we propose that the LSM theorem can be revived in the entanglement Hamiltonian when the coupling to the bath renders the system short-range correlated. Specifically, we argue that the entanglement spectrum cannot have a non-degenerate minimum, isolated by a gap from other states. We further support the results with numerical examples where a spin-[Formula: see text] system is coupled to another spin-[Formula: see text] chain serving as the bath. Compared with the original LSM theorem that primarily addresses UV-IR correspondence, our findings reveal that the UV data and topological constraints also play a pivotal role in shaping the entanglement in open quantum many-body systems.

Equilibrium figures of two liquid masses with synchronous rotation. Dynamics of a double asteroid (190166) 2005 UP156

The problem of equilibrium figures of two liquid masses in a state of tidal mutual capture is posed and solved. The condition of complete synchronous (orbital plus spin) rotation is satisfied in the system, both bodies have the same masses and congruent ellipsoidal surfaces. For each figure, in addition to its own gravity and centrifugal forces, the attraction from the second body is taken into account in the tidal approximation. The spatial form of equilibrium figures in the form of triaxial ellipsoids is found by an analytical and numerical method. It is established that the spin rotation of ellipsoidal equilibrium figures occurs not around small axes, as is usually assumed, but around the middle axes of the ellipsoids. This method is used to study the binary asteroid (190166) 2005 UP156, which approximately satisfies the initial conditions of the problem. The study showed that with the parameters known today, the system of two asteroids (190166) 2005 UP156 is nonequilibrium.

Detection of spin current generated by the acoustic spin–rotation coupling mechanism via acoustic voltage

The method of combining surface acoustic waves (SAWs) with electrical detection has promoted the study of phonon–spin coupling and spintronics. Aiming at problems of difficult detection of DC voltage and unknown origin of spin current caused by SAW in ferromagnetic/light metal systems, we constructed the Ni/Cu/Ta on LiNbO3 substrate and measured acoustic voltages directly, which are used to analyze the spin current induced by SAW. By analyzing the angular dependence of acoustic voltages and estimating the maximum spin current, it is determined that acoustic voltages originate from the acoustic spin–rotation (ASR) coupling and the acoustic spin pumping (ASP) effects. The angular dependence shows that for the longitudinal voltage, the contribution of ASR to ASP is in the ratio of 3.22/3.77, while the transverse voltage is mainly contributed by the ASR. The maximum spin current due to ASR is 0.97 × 105 A/m2, while that due to ASP is 1.47 × 105 A/m2. This work provides ideas for the design of phonon–spin coupled devices.

Clear Reduction in Spin Susceptibility and Superconducting Spin Rotation for \(H\parallel a\) in the Early-Stage Sample of Spin-Triplet Superconductor UTe2

Clear Reduction in Spin Susceptibility and Superconducting Spin Rotation for \(H\parallel a\) in the Early-Stage Sample of Spin-Triplet Superconductor UTe₂

Magnetic ground state and excitations in the mixed 3d−4d quasi-one-dimensional spin-chain oxide Sr3NiRhO6

Entanglement of spin and orbital degrees of freedom, via relativistic spin-orbit coupling, in 4d transition metal oxides can give rise to a variety of unique quantum phases. A previous study of mixed 3d−4d quasi-1D spin-chain oxide Sr3NiRhO6 using the magnetization measurements by Mohapatra [] revealed a partially disordered antiferromagnetic structure below 50 K. We here report the magnetic ground state and spin-wave excitations in Sr3NiRhO6 using muon spin rotation and relaxation (μSR), and neutron (elastic and inelastic) scattering techniques. Our neutron diffraction study reveals that in the magnetic structure of Sr3NiRhO6 Rh4+ and Ni2+ spins are aligned ferromagnetically in a spin chain, with moments along the crystallographic c axis. However, spin chains are coupled antiferromanetically in the ab plane. μSR reveals the presence of oscillations in the asymmetry-time spectra below 50 K, supporting the long-range magnetically ordered ground state. Our inelastic neutron scattering study reveals gapped quasi-1D magnetic excitations with a large ratio of gap to exchange interaction. The observed spin-wave spectrum could be well fitted with a ferromagnetic isotropic exchange model (with J=3.7 meV) and single ion anisotropy (D=10 meV) on the Ni2+ site. The magnetic excitations survive up to 85 K, well above the magnetic ordering temperature of ∼50 K, also indicating a quasi-1D nature of the magnetic interactions in Sr3NiRhO6. Published by the American Physical Society 2024

Insights on the Rotational State and Shape of Asteroid (203) Pompeja from TESS Photometry

The Main Belt asteroid (203) Pompeja shows evidence of extreme variability in visible and near-infrared spectral slope with time. The observed spectral variability has been hypothesized to be attributed to spatial variations across Pompeja’s surface. In this scenario, the observed spectrum of Pompeja is dependent on the geometry of the Sun and the observer relative to the asteroid’s spin-pole and surface features. Knowledge of the rotational spin pole and shape can be gleaned from light curves and photometric measurements. However, dense light curves of Pompeja are only available from two apparitions. Further, previous estimates of Pompeja’s sidereal period are close to being Earth commensurate, making ground-based light curves difficult to obtain. To overcome these difficulties, we implement a pipeline to extract a dense light curve of Pompeja from cutouts of Transiting Exoplanet Survey Satellite (TESS) full-frame images. We succeeded in obtaining a dense light curve of Pompeja covering ∼22 complete rotations. We measure a synodic period of P syn = 24.092 ± 0.005 hr and amplitude of 0.073 ± 0.002 mag during Pompeja’s 2021 apparition in the TESS field of view. We use this light curve to refine models of Pompeja’s shape and spin-pole orientation, yielding two spin-pole solutions with sidereal periods and spin-pole ecliptic coordinates of P sid,1 = 24.0485 ± 0.0001 hr, λ 1 = 132°, and β 1 = +41° and P sid,2 = 24.0484 ± 0.0001 hr, λ 2 = 307°, and β 2 = +34°. Finally, we discuss the implications of the derived shape and spin models for spectral variability on Pompeja.

Spin decoherence and off-resonance behavior of radio-frequency-driven spin rotations in storage rings

High-frequency driven resonant spin rotators are routinely used as standard instruments in polarization experiments in particle and nuclear physics. Maintaining the continuous exact parametric spin resonance condition of the equality of the spin rotator and the spin precession frequency during operation is one of the challenges. We present a detailed analytical description of the effects of detuning the exact spin resonance on the precessing vertical and in-plane components of the polarization. An important part of the formalism presented here is the consideration of experimentally relevant spin decoherence effects. Within the developed formalism, we address the impact of feedback via pilot-bunch-based comagnetometry on continuous spin flips and on the related interpretation of charged-particle electric dipole moment searches using storage rings. We propose a spin-flip-based tomography of the longitudinal profile of polarization in a bunch, which is important for the evaluation of the polarization-dependent luminosity in collider experiments. We emphasize the potential importance of the previously unexplored phase of the horizontal polarization of the envelope as an indicator of the stability of radio-frequency-driven spin rotations in storage rings and as a testing ground for spin decoherence mechanisms. Published by the American Physical Society 2024

Magnetic behavior of manganese doped aluminum iron oxide

This paper reports the structural and magnetic properties of undoped and manganese doped aluminum iron oxide. The samples were prepared through a conventional solid-state reaction route using the planetary ball milling technique. The XRD profile showed a body centered tetragonal crystalline behavior in a perovskite structure. The field emission scanning electron microscopy images displayed segregated grain into different clusters. The significant magnetic loss tanδ is marked for the manganese doped aluminum iron oxide, which may dissipate as heat radiation and subsequently make it suitable in thermomagnetic devices for medical related research. The well-resolved peaks as observed in the absorption of the imaginary part of the magnetic modulus correspond to the spin resonance. The characteristic frequency is detected to shift rightward and signifying the lone presence of spin rotations in the high-frequency regime. The magnitude of the imaginary part of magnetic modulus increases with both the milling time and Mn content. This implies the more absorption of magnetic energy from the alternating magnetic field that in turn leading to decrease spin rotations and follows the decreasing trend in the grain size. The release of substantial amount of heat associated with the significant magnetic loss tanδ is noticed for the sample AFMO-3 h that mark it as a suitable candidate for thermotherapy in the low-frequency regime, which may be asserted as the novelty of this study. The semicircles in their Nyquist plots represent the single magnetic relaxation of the samples and thus, an equivalent circuit may be assumed consisting of inductance and resistance in series.

Ti4Ir2O : A time reversal invariant fully gapped unconventional superconductor

Here we report muon spin rotation (μSR) experiments on the temperature and field dependence of the effective magnetic penetration depth λ(T) in the η-carbide-type suboxide Ti4Ir2O, a superconductor with a considerably high upper critical field. The temperature dependence of λ(T), obtained from transverse-field (TF)-μSR measurements, is in perfect agreement with an isotropic fully gaped superconducting state. Furthermore, our ZF μSR results confirm that the time-reversal symmetry is preserved in the superconducting state. We find, however, a remarkably small ratio of Tc/λ0−2∼1.22. This value is close to most unconventional superconductors, showing that a very small superfluid density is present in the superconducting state of Ti4Ir2O. The presented results will pave the way for further theoretical and experimental investigations to obtain a microscopic understanding of the origin of such a high upper critical field in an isotropic single-gap superconducting system. Published by the American Physical Society 2024

Unveiling nodeless unconventional superconductivity proximate to honeycomb-vacancy ordering in the Ir-Sb binary system

Vacancies in solid-state physics are underexplored in materials with strong electron-electron correlations. Recent research on the Ir-Sb binary system revealed an extended buckled-honeycomb vacancy (BHV) order. Superconductivity arises by suppressing BHV ordering through high-pressure growth with excess Ir atoms or Rh substitution, yet the superconducting pairing nature remains unknown. To explore this, we conducted muon spin rotation experiments on Ir1−δSb (synthesized at 5.5 GPa, Tc = 4.2 K) and ambient pressure synthesized optimally Rh-doped Ir1−xRhxSb (x=0.3, Tc = 2.7 K). The exponential temperature dependence of the superfluid density suggests a fully gapped superconducting state exists in both samples. The ratio of Tc to the superfluid density resembles that of unconventional superconductors. A significant increase in the superfluid density in the high-pressure synthesized sample correlates with Tc, indicating that unconventional superconductivity is intrinsic to the Ir-Sb binary system. These findings, along with the dome-shaped phase diagram, highlight IrSb as the first unconventional superconducting parent phase with ordered vacancies, requiring further theoretical investigations.

Coherent Driving of a Single Nitrogen Vacancy Center by a Resonant Magnetic Tunnel Junction.

Nitrogen vacancy (NV) centers, atomic spin defects in diamond, represent an active contender for advancing transformative quantum information science (QIS) and innovations. One of the major challenges for designing NV-based hybrid systems for QIS applications results from the difficulty of realizing local control of individual NV spin qubits in a scalable and energy-efficient way. To address this bottleneck, we introduce magnetic tunnel junction (MTJ) devices to establish coherent driving of an NV center by a resonant MTJ with voltage controlled magnetic anisotropy. We show that the oscillating magnetic stray field produced by a resonant micromagnet can be utilized to effectively modify and drive NV spin rotations when the NV frequency matches the corresponding resonance conditions of the MTJ. Our results present a new pathway to achieve all-electric control of an NV spin qubit with reduced power consumption and improved solid-state scalability for implementing cutting-edge QIS technological applications.

Depth-dependent study of time-reversal symmetry-breaking in the kagome superconductor AV3Sb5

The breaking of time-reversal symmetry (TRS) in the normal state of kagome superconductors AV3Sb5 stands out as a significant feature, but its tunability is unexplored. Using low-energy muon spin rotation and local field numerical analysis, we study TRS breaking as a function of depth in single crystals of RbV3Sb5 (with charge order) and Cs(V0.86Ta0.14)3Sb5 (without charge order). In the bulk of RbV3Sb5 (>33 nm from the surface), we observed an increase in the internal magnetic field width in the charge-ordered state. Near the surface (<33 nm), the muon spin relaxation rate is significantly enhanced and this effect commences at temperatures significantly higher than the onset of charge order. In contrast, no similar field width enhancement was detected in Cs(V0.86Ta0.14)3Sb5, either in the bulk or near the surface. These observations indicate a strong connection between charge order and TRS breaking and suggest that TRS breaking can occur prior to long-range charge order.

Microscopic probing of the superconducting and normal state properties of Ta2V3.1Si0.9 by muon spin rotation

The two-dimensional kagome lattice is an experimental playground for novel physical phenomena, from frustrated magnetism and topological matter to chiral charge order and unconventional superconductivity. A newly identified kagome superconductor, Ta2V3.1Si0.9 has recently gained attention for possessing a record high critical temperature, TC = 7.5 K for kagome metals at ambient pressure. In this study we conducted a series of muon spin rotation measurements to delve deeper into understanding the superconducting and normal state properties of Ta2V3.1Si0.9. We demonstrate that Ta2V3.1Si0.9 is a bulk superconductor with either a s+s-wave or anisotropic s-wave gap symmetry, and has an unusual paramagnetic shift in response to external magnetic fields in the superconducting state. Additionally, we observe an exceptionally low superfluid density − a distinctive characteristic of unconventional superconductivity − which remarkably is comparable to the superfluid density found in hole-doped cuprates. In its normal state, Ta2V3.1Si0.9 exhibits a significant increase in the zero-field muon spin depolarisation rate, starting at approximately 150 K, which has been observed in other kagome-lattice superconductors, and therefore hints at possible hidden magnetism. These findings characterise Ta2V3.1Si0.9 as an unconventional superconductor and a noteworthy new member of the vanadium-based kagome material family.

Polymethylmethacrylate (PMMA) deposition and removal optimization in CVD-grown graphene transfer: A Taguchi technique study

The conventional method of graphene transfer involving Polymethylmethacrylate (PMMA) often results in residual PMMA, negatively impacting the optical and electrical properties of the transferred graphene layer. This study employs the Taguchi optimization technique to minimize PMMA contamination during the graphene transfer process. The quality of the transferred graphene layer was evaluated utilizing atomic force microscopy (AFM), Raman spectroscopy, and Hall Effect measurement. The optimized conditions identified were a PMMA concentration (P) of 4.5 %, a spin rotation (S) speed of 3000 rpm, an acetone bath temperature (A) at 40 °C, and a dissolution duration (T) of 60 min. These parameters achieved a promising surface coverage of 3.42 %. Interestingly, further characterization highlighted that sample #8, prepared with different parameters (P = 12 %, S = 3000 rpm, A = 24 °C, T = 60 min), exhibited a surface coverage of 5.10 % and superior properties, including high transparency, exceptional film quality, low electrical resistance (8691 Ω), and an ID/IG ratio of 0.13. These findings suggest that the optimized conditions are suitable for applications prioritizing surface coverage, while the parameters for sample #8 are recommended for achieving minimal electrical resistance, high transparency, and superior film quality. This research contributes insights into PMMA-assisted graphene transfer, offering practical guidance for tailored processes.

Magnetically Tunable Electric Dipolar Interactions of Ultracold Polar Molecules in the Quantum Ergodic Regime.

By leveraging the hyperfine interaction between the rotational and nuclear spin degrees of freedom, we demonstrate extensive magnetic control over the electric dipole moments, electric dipolar interactions, and ac Stark shifts of ground-state alkali-dimer molecules such as KRb(X^{1}Σ^{+}). The control is enabled by narrow avoided crossings and the highly ergodic character of molecular eigenstates at low magnetic fields, offering a general and robust way of continuously tuning the intermolecular electric dipolar interaction for applications in quantum simulation, quantum sensing, and dipolar spinor physics.

All-Optical Trapping and Programmable Transport of Gold Nanorods with Simultaneous Orientation and Spinning Control.

Gold nanorods (GNRs) are of special interest in nanotechnology and biomedical applications due to their biocompatibility, anisotropic shape, enhanced surface area, and tunable optical properties. The use of GNRs, for example, as sensors and mechanical actuators, relies on the ability to remotely control their orientation as well as their translational and rotational motion, whether individually or in groups. Achieving such particle control by using optical tools is challenging and exceeds the capabilities of conventional laser tweezers. We present a tool that addresses this complex manipulation problem by using a curve-shaped laser trap, enabling the optical capture and programmable transport of single and multiple GNRs along any trajectory. This type of laser trap combines confinement and propulsion optical forces with optical torque to transport the GNRs while simultaneously controlling their rotation (spinning) and orientation. The proposed system facilitates the light-driven control of GNRs and the quantitative characterization of their motion dynamics including transport speed, spinning frequency, orientation, and confinement strength. We experimentally demonstrate that remote control of the GNRs can be achieved both near a substrate surface (2D trapping) and deep within the sample (3D all-optical trapping). The motion dynamics of two sets of off-resonant GNRs, possessing similar aspect ratios but different resonance wavelengths, are analyzed to highlight the role played by their optical and mechanical properties in the optical manipulation process. The experimental results are supported by a theoretical model describing the observed motion dynamics of the GNRs. This optical manipulation tool can significantly facilitate applications of light-driven nanorods.

Electron Localization Function for Noncollinear Spins.

Understanding of bonding is key to modeling materials and predicting properties thereof. A widely adopted indicator of bonds and atomic shells is the electron localization function (ELF). The building blocks of the ELF are also used in the construction of modern density functional approximations. Here, we demonstrate that the ELF breaks down when applied beyond regular nonrelativistic quantum states. We show that for tackling general noncollinear open-shell solutions, it is essential to address both the U(1) gauge invariance, i.e., invariance under a multiplication by a position dependent phase factor, and SU(2) gauge invariance, i.e., invariance under local spin rotations, conjointly. Remarkably, we find that the extended ELF also improves the description of paradigmatic collinear states.

Thermodynamics of a rotating hadron resonance gas with van der Waals interaction

Studying the thermodynamics of the systems produced in ultra-relativistic heavy-ion collisions is crucial in understanding the QCD phase diagram. Recently, a new avenue has opened regarding the implications of large initial angular momentum and subsequent vorticity in the medium evolution in high-energy collisions. This adds a new type of chemical potential into the partonic and hadronic systems, called the rotational chemical potential. We study the thermodynamics of an interacting hadronic matter under rotation, formed in an ultra-relativistic collision. We introduce attractive and repulsive interactions through the van der Waals equation of state. Thermodynamic properties like the pressure (P), energy density (ε\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varepsilon $$\\end{document}), entropy density (s), trace anomaly ((ε-3P)/T4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(\\varepsilon - 3P)/T^{4}$$\\end{document}), specific heat (cv\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c_\ extrm{v}$$\\end{document}) and squared speed of sound (cs2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c_\ extrm{s}^{2}$$\\end{document}) are studied as functions of temperature (T) for zero and finite rotation chemical potential. The conserved charge fluctuations, which can be quantified by their respective susceptibilities, are also studied. The rotational (spin) density corresponding to the rotational chemical potential is explored. In addition, we explore the possible liquid–gas phase transition in the hadron gas with van der Waals interaction in the T – ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega $$\\end{document} phase space.