Low-Temperature Specific-Heat of One-Dimensional Hubbard Model

Rui‐Hong Yue, Tetsuo Deguchi

The magnetic susceptibility and the low-temperature specific heat of the one-dimensional Hubbard model under the integrable open-boundary conditions are discussed through the Bethe ansatz with the string hypothesis. The contributions of the boundary fields to both the susceptibility and the specific heat are obtained, and their exact expressions are analytically derived.

Thereza Paiva, Carey Huscroft, Andrew K. McMahan +1 more

Richard Smith

E.J. Calegari, Cesar Lobo, S. G. Magalhães +2 more

Minoru Takahashi

Low-temperature specific heat per site (C) of one-dimensional Hubbard model is investigated by the method of non-linear integral equations. For the half-filled case we show lim H →0 lim T →0C / T = πI0( π/ 2 U )/( 6 I1(π/ 2 U ) ), where T is temperature, H is magnetic field, U is the coupling constant, and I0 and I1 are modified Bessel functions. Although this equation yields lim T, H →0C / T = π/ 6 in the limit U →0+, the true value of lim T, H →0C / T at U = 0 is π/ 3. This means that lim T, H →0C / T is a discontinuous function of U at U = 0. This discontinuity disappears when the band is not half filled.

Daniel Duffy, Adriana Moreo

Quantum Monte Carlo results for the specific heat c of the two-dimensional Hubbard model are presented. At half filling it was observed that c\ensuremath{\sim}${\mathrm{T}}^{2}$ at very low-temperatures. Two distinct features were also identified: a low-temperature peak related to the spin degrees of freedom and a higher-temperature broad peak related to the charge degrees of freedom. Away from half filling the spin-induced feature slowly disappears as a function of hole doping while the charge feature moves to lower temperature. A comparison with experimental results for the high-temperature cuprates is discussed.