Spin coherent states play a crucial role in defining QESM (quasi-exactly solvable models) establishing a strict correspondence between energy spectra of spin systems and low-lying quantum states for a particle moving in a potential field of a certain form. Spin coherent states are also used for finding the Wigner-Kirkwood expansion and quantum corrections to energy quantization rules. The close...

The Davydov D1 ansatz, which assigns individual bosonic trajectories to each spin state, is an efficient, yet extremely accurate trial state for time-dependent variation of the sub-Ohmic spin-boson model [N. Wu, L. Duan, X. Li, and Y. Zhao, J. Chem. Phys. 138, 084111 (2013)]. A surface hopping algorithm is developed employing the Davydov D1 ansatz to study the spin dynamics with a sub-Ohmic bos...

We use the vacuum Rabi splitting to perform quantum nondemolition measurements that prepare a conditionally spin squeezed state of a collective atomic psuedospin. We infer a 3.4(6) dB improvement in quantum phase estimation relative to the standard quantum limit for a coherent spin state composed of uncorrelated atoms. The measured collective spin is composed of the two-level clock states of ne...

We propose a new approach to the measurement of a single spin state, based on nuclear magnetic resonance (NMR) techniques and inspired by the coherent control over many-body systems envisaged by quantum information processing. A single target spin is coupled via the magnetic dipolar interaction to a large ensemble of spins. Applying radio frequency pulses, we can control the evolution so that t...

It is a great honor to edit a special issue of Applied Magnetic Resonance, in particular if the area presented is not magnetic resonance spectroscopy itself. The topic of this special issue, spin chemistry [1], can be considered as upspring of magnetic resonance spectroscopy. On the other hand, the field of spin chemistry contributed significantly to the methodological improvement of both NMR a...

Remarkable efforts in the study of the semi-classical regime of kinematical loop quantum gravity are currently underway. In this note, we construct a “quasi-coherent” weave state using Gaussian factors. In a similar fashion to some other proposals, this state is peaked in both the connection and the spin network basis. However, the state constructed here has the novel feature that, in the spin ...

We consider strongly interacting systems of effective spins, subject to dissipative spin-flip processes associated with optical pumping. We predict the existence of novel magnetic phases in the steady state of this system, which emerge due to the competition between coherent and dissipative processes. Specifically, for strongly anisotropic spin-spin interactions, we find ferromagnetic, antiferr...

The disclosure of spinon superconductivity and superconductivity mediated by spin-waves in hole-doped Bi 2 Sr 2 CaCu 2 O 8+x (Bi2212) cuprate raises the question about the origin of the superconductivity in other cuprates and specially in an electron-doped Nd 2-x Ce x CuO 4 (NCCO) cuprate. The superconductivity (SC) in copper-oxide materials or the high-T c superconductivity (HTSC) is an extrao...