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We propose and analyze a generalization of the Kitaev chain for fermions with long-range p-wave pairing, which decays with distance as a power-law with exponent $\alpha$. Using the integrability of the model, we demonstrate the existence of two types of gapped regimes, where correlation functions decay exponentially at short range and algebraically at long range ($\alpha > 1$) or purely algebraically ($\alpha < 1$). Most interestingly, along one of the two critical lines, long-range pairing is found to break conformal symmetry for $\alpha \leq 3/2$. This is accompanied by the violation of the area law for the entanglement entropy in large parts of the phase diagram in the presence of a gap, and can be detected via the dynamics of entanglement following a quench. Some of these features may be relevant for current experiments with cold atomic ions.
Vodola, D.
, Lepori, L.
, Ercolessi, E.
, Gorshkov, A.
and Pupillo, G.
(2014),
Kitaev chains with long-range interactions, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevLett.113.156402, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=916113
(Accessed October 12, 2025)