Café com Física



13 de setembro de 2017
Sala 18 (Cristalografia)

Dimitrios Voliotis

Shannon-Rényi entropies in quantum aperiodic spin chains via block real-space renormalization

Recently, another version of a real-space RG approach proposed by Fernandez-Pacheco [1], successfully located the critical point and the critical exponents of the pure and random Ising chain. The revisited method [2,3] renormalizes a block of spins, confirming by much easer way than by conformal field theory (CFT), the multifractal dimension and multifractal spectrum for the quantum Ising chain [4]. We extended this argument to aperiodic spin chains with specific substitution rules by studying the Shannon-Renyi entropies of the ground state wave function. We extract the multifractal dimension and spectrum, comparing them with the pure and random case [4]. Both quantities found to vary with the coupling ratio but to be independent of the wandering exponent of the sequence. Finally, by a simple analogy we extended the studies into the excited states.

[1 ] G. Fernandez-Pacheco, Phys. Rev. D 19, 3173 (1979).
[2] J. Miyazaki and H. Nishimori , Phys. Rev. E 87, 032154 (2013).
[3] C. Monthus, J. Stat. Mech. P01023 (2015).
[4] C. Monthus, J. Stat. Mech. P04007 (2015).