Floquet-induced $p_x+ip_y$ bosonic pair condensate

Abstract

In this study, we propose a dynamical pairing mechanism other than the pair-wise interactions. Starting from a two-dimensional hard-core boson model with periodically modulated hopping amplitude, we derive an effective Floquet Hamiltonian with three-site interactions that are responsible for unconventional pairing between adjacent bosons. By performing a density matrix renormalization group study on this three-site interacting Hamiltonian, we reveal a bosonic pair condensate with $p_x+ ip_y$ symmetry, while the single-particle Bose-Einstein condensate is completely depleted. The experimental implementations of the proposed model on polar molecular systems and superconducting quantum circuit have also been discussed.

Figures (5)

• Figure 1: Sketch of the original hard-core boson Hamiltonian with periodic modulation of the hopping amplitude and the time-independent Floquet Hamiltonian (at high frequency) with correlated hopping.
• Figure 2: (a) Dark Fock states $|\sigma_D\rangle$ of $H^1$ in a single plaquette ($H^1|\sigma_D\rangle=0$). (b) The 4 Fock states outside the dark state manifold in a single plaquette, each of which is connected to two others via $H^1$.
• Figure 3: The evolution of the average distance between the two bosons $r(t)$ in a two-leg ladder ($12\times 2$) system at different driving frequencies.
• Figure 4: The correlation functions in the ground state of $H^1$ in 2D cylindrical lattice with a fixed $L_x=64$ and various $L_y$ at 1/8 filling. (a) The single particle correlation functions; (b)the pair correlations between a vertical bond and another vertical bond; (c) the pair correlations between a vertical bond and a horizontal bond.
• Figure 5: The single-particle and pair correlation in the ground state of $H^1$ in 2D cylindrical lattice with a $L_x=32$ and $L_y=4$ at half filling.