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Showing 1 to 20 of 66 for “"spin-1/2"”.
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Synthesis, structure, and magnetic properties of spin-1/2 kagomé antiferromagnets
… a kagomé because they exhibit strong geometric spin frustration and are predicted to show no magnetic long-range ordering (LRO). The three broad classes of kagomé layered materials presented herein--covalently linked layers, hydrogen-bonded layers, and electrostatically linked layers--reflect …
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The one-dimensional spin-1/2 ANNNI model in non-commuting magnetic fields
… thesis we have investigated the one-dimensional spin-1/2 Axial Next Nearest Neighbour Ising (ANNNI) model in non-commuting magnetic fields. As a starting point we obtained an estimate of the phase diagram of the model by treating the spins as classical vectors. This was followed by an …
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¹⁷O and ⁶³Cu NMR study of spin dynamics in low-dimensional spin 1/2 antiferromagnets
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1999.
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Novel magnetic and superconducting states in spin-1/2 kagome lattice and its doped variant
Quantum spin liquids, which are quantum ground states of interacting spin systems that break no symmetries, have long been a fascination among the theoretical condensed matter community. After years of experimental searches, several promising candidates finally emerged, including herbertsinithite …
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Quantenmechanische Feinstruktur und molekulare Dynamik gekoppelter Spin-1/2-Systeme in der In-vivo-NMR-Spektroskopie
… und am lebenden Gewebe (in vivo) wurden die Spin-1/2-Systeme der körpereigenen Metaboliten Kreatin, Taurin, Citrat, Carnosin und Adenosin-5'-triphosphat (ATP) mit 1H-NMR-Spektroskopie bzw. 31P-NMR-Spektroskopie (für ATP) an einem konventionellen Ganzkörper-MR-Tomographen bei 1,5 T untersucht. …
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Elastic and inelastic X-ray scattering studies of the low dimensional spin-1/2 quantum magnet TiOCl
The ground state for a one dimensional spin 1/2 Heisenberg chain coupled to phonons is a dimerized singlet state known as a "spin-Peierls" state. Currently, the spin-Peierls state is realized in only a handful of known compounds. Even after decades of scientific scrutiny, there is an absence of …
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Sobre a medida de emaranhamento, via distância entre estados, em cadeias de Heisenberg antiferromagnéticas de spin-1/2
… cálculo do emaranhamento para vários sistemas de spin-1/2 que satisfaçam a hamiltoniana de Heisenberg 1D, anisotrópica, sem campo magnético externo e com interação antiferromagnética. Além de sistemas dímeros, estudaremos o emaranhamento em sistemas trímeros, cadeias de Heisenberg infinitas e …
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Nmr Line Shape and Moment Analyses for a Spin-1/2 Nucleus in Polycrystalline, Rigid Lattice, Axially Symmetric Systems
Made available in DSpace on 2014-12-09T17:36:08Z (GMT). No. of bitstreams: 1 6901472.pdf: 2681617 bytes, checksum: 45b3ab26360545903d8efcf723d05cd2 (MD5) Previous issue date: 1968
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Thermodynamic and neutron scattering study of the spin- 1/2 kagome antiferromagnet ZnCu₃(OH)₆Cl₂ : a quantum spin liquid system
New physics, such as a quantum spin liquid, can emerge in systems where quantum fluctuations are enhanced due to reduced dimensionality and strong frustration. The realization of a quantum spin liquid in two-dimensions would represent a new state of matter. It is believed that spin liquid physics …
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The ground state of the spin-1/2 kagomé lattice antiferromagnet : neutron scattering studies of the zinc-paratacamite mineral family
… the nature of the ground state of the spin-1 2 kagomé lattice antiferromagnet, as such a system is considered ideal for the emergence of spin liquid physics. Clinoatacamite, a distorted kagomé lattice antiferromagnet with weak inter-plane coupling, undergoes a Néel or- dering transition …
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Ground States through Variational Optimization using Matrix Product States: a comparison between open and periodic boundary conditions
… der Grundzustandsenergien des kritischen Spin-1/2 Heisenberg- und des transversalen Spin-1/2 Ising-Modells in einer Raumdimension. Wir vergleichen offene Randbedingungen (obc) mit periodischen Randbedingungen (pbc). Im Falle von pbc testen wir verschiedene Methoden zur Verbesserung der …
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Exotic phenomena in rare-earth based geometrically frustrated magnets
… are of specific interest due to the strong spin-orbit coupling and crystal electric field effects, which split the degenerate 4f angular momentum states, often leading to an effective spin-1/2 doublet with anisotropic effective exchange models. For this reason, RE materials are paramount to …
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Terahertz spectroscopy of quantum spin liquids
The optical properties of the spin-1/2 kagome lattice antiferromagnetic Herbertsmithite, ZnCu₃(OH)₆Cl₂, are studied by means of Terahertz Time-Domain Spectroscopy. Herbertsmithite is proposed to exhibit Quantum Spin Liquid behavior, in which electron spins have strong antiferromagnetic …
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Aspects of quantum states of matter
… concerning the eigenstates and spectra of spin-0 and spin-1/2 quantum fields confined to two-dimensional planes and spheres, in homoge-neous magnetic field configurations. We then study a novel variation of Haldane's spherical monopole system called the spherical dipole system. We review …
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Dynamical correlations of S=1/2 quantum spin chains
Spin-1/2 chains demonstrate some of the striking effects of interactions and quantum fluctuations in one-dimensional systems. The XXZ model has been used to study the unusual properties of anisotropic spin chains in an external magnetic field. The zero temperature phase diagram for this model …
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Two topics in non-perturbative lattice field theories : the U(1) quantum link model and perfect actions for scalar theories
… idea of the loop-cluster algorithm for quantum spins, we present the construction of a flux-cluster algorithm for the U(1) quantum link model for the spin-1/2 quantization of the electric flux. It is shown how improved estimators for Wilson loop expectation values can be defined. This is …
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Study of ferromagnetic systems with many phase transitions
… was performed for a translation invariant spin 1/2 ferromagnetic model in Z² with fundamental bonds A = {(0,0);(0,1)} B = {(0,0);(2,0)} C = {(0,0);(0,1);(1,1);(1,0)} The model exhibits one phase transition if the coupling constant J(A) is zero, but two phase transitions were found when J(A) …
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Semiklassische Beschreibung des Spin-Boson-Modells
The spin coherent state path integral describing the dynamics of a <br>spin-1/2-system in a magnetic field of arbitrary <br>time-dependence is considered. Defining the path integral as the limit <br>of a Wiener regularized expression, the semiclassical approximation <br>leads to a continuous …
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A search for a new phonon detector
… studied was the use of a magnetically tuned spin 1/2 system whose change in magnetization with incident phonon flux can be monitored by a pick-up coil coupled to a SQUID magnetometer. Time-of-flight measurements versus pressure and tuning magnetic field were made to test the detection …
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Progress towards an optimized ¹²⁹Xe / ³He Zeeman maser and a test of boost symmetry
… measurement of the ¹²⁹Xe and ³He nuclear spin-1/2 Zeeman transition frequencies [2, 3, 4]. The optimized ¹²⁹Xe /³He maser will be used for highly sensitive tests of Lorentz and CPT symmetry.
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