Related papers: Intrinsic and extrinsic nonstationary field-driven…
A 2-level spin-system of cold sodium atoms is proposed. Both the cases that the system has arrived at thermo-equilibrium and is in the early stage of evolution have been studied. This system is inert to the magnetic field $B$ in general but…
We report on the origin of spin freezing in the disordered fluorite Ho$_2$Zr$_2$O$_7$. The system is investigated by low-temperature heat capacity as well as by DC and AC magnetization. While the system does not show a long-range magnetic…
We provide experimental and numerical evidence for thermal excitations within and among magnetic mesospins, forming artificial spin ice structures. At low temperatures, a decrease in magnetization and increase in susceptibility is observed…
Ultrasound velocity measurements were performed on a single crystal of spin-frustrated ferrite spinel ZnFe$_2$O$_4$ from 300 K down to 2 K. In this cubic crystal, all the symmetrically-independent elastic moduli exhibit softening with a…
Periodic spatial modulations of the superfluid density, or pair density waves, have now been widely detected in unconventional superconductors, either as the primary or the secondary states accompanying charge density waves. Understanding…
We discuss anomalous decoherence effects at zero and finite temperatures in driven coupled quantum spin systems. By numerical simulations of the quantum master equation, it is found that the entanglement of two coupled spin qubits exhibits…
Ultracold atomic spin mixtures develop rich and intriguing magnetic properties when an external radiation coherently couples different spin states. In particular, the coupled mixture may acquire a critical behavior when the spin…
We present an experimental determination of the isothermal magnetic susceptibility of the spin ice materials Dy2Ti2O7 and Ho2Ti2O7 in the temperature range 1.8-300 K. The use of spherical crystals has allowed the accurate correction for…
While sources of magnetic fields - magnetic monopoles - have so far proven elusive as elementary particles, several scenarios have been proposed recently in condensed matter physics of emergent quasiparticles resembling monopoles. A…
We report on the experimental evidences for an unusual coupling between the magnetic field- induced fluctuations of correlated Ce-ions coinciding with the discontinuous movement of the underlying spin density wave in the intermetallic rare…
We discuss the theory of spin waves in non-degenerate ultra-cold gases, and compare various methods which can be used to obtain appropriate kinetic equations. We then study non-hydrodynamic situations, where the amplitude of spin waves is…
The spin ice materials Ho$_{2}$Ti$_{2}$O$_{7}$ and Dy$_{2}$Ti$_{2}$O$_{7}$ are by now perhaps the best-studied classical frustrated magnets. A crucial step towards the understanding of their low temperature behaviour -- both regarding their…
We present muon spin relaxation ($\mu$SR) and specific-heat versus temperature $C(T)$ measurements on polycrystalline and single-crystal samples of the pyrochlore magnet Yb$_2$Ti$_2$O$_7$. $C(T)$ exhibits a sharp peak at a $T_\mathrm{C}$ of…
We report on the non-equilibrium monopole dynamics in the classical spin ice Dy$_2$Ti$_2$O$_7$ detected by means of high-resolution magnetostriction measurements. Significant lattice changes occur at the transition from the kagome-ice to…
While the spin dynamics of La$_{0.7}$Ca$_{0.3}$MnO$_3$ in the ferromagnetic phase are known to be unconventional, previous measurements have yielded contradictory results regarding the damping of spin wave excitations. Neutron spectroscopy…
We investigate the thermodynamic properties of FeSe under the in-plane magnetic fields using torque magnetometry, specific heat, magnetocaloric measurements. Below the upper critical field Hc2, we observed the field-induced anomalies at H1…
Pulsed neutron spectroscopy is used to make absolute measurements of the dynamic magnetic susceptibility of insulating YBa2Cu3O6.15. Acoustic and optical modes, derived from in- and out-of-phase oscillation of spins in adjacent CuO2 planes,…
The high temperature limit of interacting spins is usually not associated with ordering or critical phenomena. Nevertheless, spontaneous fluctuations of a local spin polarization at equilibrium have nontrivial dynamics even in this limit.…
We show that two-component Bose-Einstein condensed mixtures, in presence of a persistent current, exhibit a non trivial Doppler shift of the sound velocities. The peculiarity is due to the inter-species interaction and the possibility of…
To gain control over magnetic order on ultrafast time scales, a fundamental understanding of the way electron spins interact with the surrounding crystal lattice is required. However, measurement and analysis even of basic collective…