Antiferromagnetic spin correlation of SU( $\mathcal{N}$ ) Fermi gas in an optical dimerized latticeAntiferromagnetic spin correlation of SU($\mathcal{N}$) Fermi gas in an optical dimerized lattice

Hideki Ozawa, Shintaro Taie, Yosuke Takasu +1 more

We report on the observation of nearest-neighbor antiferromagnetic spin correlations of a Fermi gas with SU( $\mathcal{N}$ ) symmetry trapped in an optical dimerized lattice. Quantum magnetism originates from the superexchange interaction between quantum-mechanical spins. By using a dimerized cubic configuration, we enhance the superexchange coupling within the dimer, which gives rise to an excess of singlets compared with triplets consisting of two different spins. The precise control of the spin degrees of freedom provided by an optical pumping technique enables us a straightforward comparison between the cases of SU(2) and SU(4). Our important finding is that the antiferromagnetic correlation is enhanced for the SU(4)-spin system compared with SU(2) as a consequence of a Pomeranchuk cooling effect. This work is an important step towards the realization of novel SU( $\mathcal{N}>2$ ) quantum magnetism.We report on the observation of nearest-neighbor antiferromagnetic spin correlations of a Fermi gas with SU($\mathcal{N}$) symmetry trapped in an optical dimerized lattice. Quantum magnetism originates from the superexchange interaction between quantum-mechanical spins. By using a dimerized cubic configuration, we enhance the superexchange coupling within the dimer, which gives rise to an excess of singlets compared with triplets consisting of two different spins. The precise control of the spin degrees of freedom provided by an optical pumping technique enables us a straightforward comparison between the cases of SU(2) and SU(4). Our important finding is that the antiferromagnetic correlation is enhanced for the SU(4)-spin system compared with SU(2) as a consequence of a Pomeranchuk cooling effect. This work is an important step towards the realization of novel SU($\mathcal{N}>2$) quantum magnetism.

Jan 18, 20182 citations

Quantized geometry associated with uncertainty and correlation

Sumiyoshi Abe

The geometric structure of the law of quantum-state evolution is studied. The Fubini-Study metric induced on the quantum evolution submanifold of the projective Hilbert space is shown to be completely expressed by the uncertainties and correlations of various generators of evolutions. The Riemannian connection is expressed as a quantum-mechanical expectation value of a certain Hermitian operator. It is discussed that the metric carries some of quantum numbers contained in a given reference state, in general, and consequently the geometry is inherently quantized. These results are demonstrated by the simple examples of the squeezed coherent state, displaced number state, squeezed number state, and generalized coherent spin state.The geometric structure of the law of quantum-state evolution is studied. The Fubini-Study metric induced on the quantum evolution submanifold of the projective Hilbert space is shown to be completely expressed by the uncertainties and correlations of various generators of evolutions. The Riemannian connection is expressed as a quantum-mechanical expectation value of a certain Hermitian operator. It is discussed that the metric carries some of quantum numbers contained in a given reference state, in general, and consequently the geometry is inherently quantized. These results are demonstrated by the simple examples of the squeezed coherent state, displaced number state, squeezed number state, and generalized coherent spin state.

Physical Review ADec 1, 199348 citations

Quantum Coherence and Quantum Correlations

Gerard J. Machado

Jul 9, 20170 citations

Time as a consequence of internal coherence

Leandro R. S. Mendes, Diogo O. Soares-Pinto

Time has been an elusive concept to grasp. Although we do not yet understand it properly, there have been advances made in regard to how we can explain it. One such advance is the Page-Wootters mechanism. In this mechanism, time is seen as an inaccessible coordinate and the apparent passage of time arises as a consequence of correlations between the subsystems of a global state. Here we propose a measure that captures the relational character of the mechanism, showing that the internal coherence is the necessary ingredient for the emergence of time in the Page-Wootters model. Also, we connect it to results in quantum thermodynamics, showing that it is directly related to the extractable work from quantum coherence.Time has been an elusive concept to grasp. Although we do not yet understand it properly, there have been advances made in regard to how we can explain it. One such advance is the Page-Wootters mechanism. In this mechanism, time is seen as an inaccessible coordinate and the apparent passage of time arises as a consequence of correlations between the subsystems of a global state. Here we propose a measure that captures the relational character of the mechanism, showing that the internal coherence is the necessary ingredient for the emergence of time in the Page-Wootters model. Also, we connect it to results in quantum thermodynamics, showing that it is directly related to the extractable work from quantum coherence.

arXiv:1806.09669Proceedings of the Royal Society A Mathematical Physical and Engineering SciencesNov 1, 201924 citations

Antiferromagnetic spin correlation of SU(

\mathcal{N}

) Fermi gas in an optical dimerized lattice

We report on the observation of nearest-neighbor antiferromagnetic spin correlations of a Fermi gas with SU(

\mathcal{N}

) symmetry trapped in an optical dimerized lattice. Quantum magnetism originates from the superexchange interaction between quantum-mechanical spins. By using a dimerized cubic configuration, we enhance the superexchange coupling within the dimer, which gives rise to an excess of singlets compared with triplets consisting of two different spins. The precise control of the spin degrees of freedom provided by an optical pumping technique enables us a straightforward comparison between the cases of SU(2) and SU(4). Our important finding is that the antiferromagnetic correlation is enhanced for the SU(4)-spin system compared with SU(2) as a consequence of a Pomeranchuk cooling effect. This work is an important step towards the realization of novel SU(

\mathcal{N}>2

) quantum magnetism.