The behavior of fermions with two spin states that interact with a large scattering length is constrained by universal relations that hold for any state of the system. These relations involve a central property of the system called the contact, which measures the number of pairs of fermions with different spins that have small separations. The contact controls the thermodynamics of the system as well as the large-momentum and high-frequency tails of correlation functions. This review summarizes the current theoretical and experimental status of these universal relations.The behavior of fermions with two spin states that interact with a large scattering length is constrained by universal relations that hold for any state of the system. These relations involve a central property of the system called the contact, which measures the number of pairs of fermions with different spins that have small separations. The contact controls the thermodynamics of the system as well as the large-momentum and high-frequency tails of correlation functions. This review summarizes the current theoretical and experimental status of these universal relations.

arXiv:1008.2922Aug 17, 20102 citations

On the description of nearly ferromagnetic fermion systems

J. R. Schrieffer, N. F. Berk

Physics Letters AMay 1, 196716 citations

Relation between two measures of entanglement in spin- 1∕2 and spinless fermion quantum chain systems

Xiao‐Feng Qian, Z. Song

The concepts of concurrence and mode concurrence are the measures of entanglement for spin- $1∕2$ and spinless fermion systems, respectively. Based on the Jordan-Wigner transformation, any spin- $1∕2$ system is always associated with a fermion system (called the counterpart system). A comparison of concurrence and mode concurrence can be made with the aid of Marshall's sign rule for the ground states of spin- $1∕2$ $XXZ$ and spinless fermion chain systems. We observe that there exists an inequality between concurrence and mode concurrence for the ground states of the two corresponding systems. The spin- $1∕2$ $XY$ chain system and its spinless fermion counterpart as a realistic example are discussed to demonstrate the analytical results.The concepts of concurrence and mode concurrence are the measures of entanglement for spin-$1∕2$ and spinless fermion systems, respectively. Based on the Jordan-Wigner transformation, any spin-$1∕2$ system is always associated with a fermion system (called the counterpart system). A comparison of concurrence and mode concurrence can be made with the aid of Marshall's sign rule for the ground states of spin-$1∕2$ $XXZ$ and spinless fermion chain systems. We observe that there exists an inequality between concurrence and mode concurrence for the ground states of the two corresponding systems. The spin-$1∕2$ $XY$ chain system and its spinless fermion counterpart as a realistic example are discussed to demonstrate the analytical results.

arXiv:quant-ph/0604108Physical Review AAug 2, 20062 citations

On the Relation between Fermions and Bosons

Morikazu TODA

Total mean curvature and submanifolds of finite typeOct 1, 19930 citations

Quantum spin systems, fermi systems and group extensions

Ph. Combe, R. Rodriguez, M. Sirugue +1 more

Springer eBooksApr 6, 20080 citations

Equivalent relation between quantum entanglement and steering in two-fermion spin systems under static magnetic fields

Xiao‐Gang Fan, Xin-Yu Yang, Wen‐Yang Sun +4 more

Abstract Quantum entanglement and steering are both fundamental concepts for describing quantum correlations, with steerable states forming a strict subset of entangled states. In general two-qubit systems, the relation between entanglement and steering can be characterized by an inequality, referred to as the constraint relation. In this work, we investigate a two-fermion spin system to explore the influence of static magnetic fields on quantum entanglement and steering. Our results demonstrate that entanglement and steering are equivalent in this system. The finding provides new perspectives for understanding quantum correlations in two-fermion spin systems. Furthermore, we examine the dynamic behavior of entanglement, showing that the maximum entanglement of this system affected by both external and internal factors.Abstract Quantum entanglement and steering are both fundamental concepts for describing quantum correlations, with steerable states forming a strict subset of entangled states. In general two-qubit systems, the relation between entanglement and steering can be characterized by an inequality, referred to as the constraint relation. In this work, we investigate a two-fermion spin system to explore the influence of static magnetic fields on quantum entanglement and steering. Our results demonstrate that entanglement and steering are equivalent in this system. The finding provides new perspectives for understanding quantum correlations in two-fermion spin systems. Furthermore, we examine the dynamic behavior of entanglement, showing that the maximum entanglement of this system affected by both external and internal factors.

Chinese Physics BFeb 12, 20260 citations

The concepts of concurrence and mode concurrence are the measures of entanglement for spin-

1∕2

and spinless fermion systems, respectively. Based on the Jordan-Wigner transformation, any spin-

1∕2

system is always associated with a fermion system (called the counterpart system). A comparison of concurrence and mode concurrence can be made with the aid of Marshall's sign rule for the ground states of spin-

1∕2

XXZ

and spinless fermion chain systems. We observe that there exists an inequality between concurrence and mode concurrence for the ground states of the two corresponding systems. The spin-

1∕2

XY

chain system and its spinless fermion counterpart as a realistic example are discussed to demonstrate the analytical results.