Prof Radu Coldea

Abstract:

The deposited package contains experimental single crystal inelastic neutron scattering data probing the spin dynamics in the quantum Ising chain magnet CoNb2O6 in applied transverse magnetic field together with corresponding theoretical calculations of the spin dynamics. A matlab script to read and plot all data in ASCII files is also supplied.

Abstract:

The deposited package contains experimental single crystal inelastic neutron scattering data probing the spin dynamics in the quantum Ising chain magnet CoNb2O6 in longitudinal magnetic field together with corresponding theoretical calculations of the spin dynamics. A matlab script to read and plot all data in ASCII files is also supplied.

Abstract:

The lack of methods to experimentally detect and quantify entanglement in quantum matter impedes our ability to identify materials hosting highly entangled phases, such as quantum spin liquids. We thus investigate the feasibility of using inelastic neutron scattering (INS) to implement a model-independent measurement protocol for entanglement based on three entanglement witnesses: one-tangle, two-tangle, and quantum Fisher information (QFI). We perform high-resolution INS measurements on Cs2CoCl4, a close realization of the S = 1/2 transverse-field XXZ spin chain, where we can control entanglement using the magnetic field, and compare with density-matrix renormalization group calculations for validation. The three witnesses allow us to infer entanglement properties and make deductions about the quantum state in the material. We find QFI to be a particularly robust experimental probe of entanglement, whereas the one- and two-tangles require more careful analysis. Our results lay the foundation for a general entanglement detection protocol for quantum spin systems