Atom-molecule conversion with quantum manipulations

Abstract

In this paper, we investigate quantum manipulations in an open atom-molecule conversion system. Through the transformation for the basis of the system, a set of time-dependent equations are derived under mean field approximation. We find that transitions between different dynamic areas of the system can be realized through manipulating an external rotating magnetic field, which corresponds to the tunneling rate in the equation. Through investigating the phase space of the system, we design an efficient method to combine pure cold molecule and pure molecular state so that it can be reached with much shorter time. Furthermore, manipulation of laser signal modulation, external diving and the distance-selective diffusion are also discussed in this paper.

Quantum phase transition of a modified spin-boson model

“…Consider a general state expanded by the Fock state, i.e., |ψ = N i=0 c i |i , the density operator reads ρ = |ψ ψ| = i,i c i c * i |i i | and the reduced density operator for the bosonic molecule (can The offset between q N and q c as a function of N, (b) the minimum energy gap Δ min as a function of N, and (c) the minimum energy gap Δ min as a function of the offset between q N and q c for different c with f = 1. Black solid lines show our fitting results given by equations ( 4)- (6). From (a) to (c), the slopes of the fitting lines are − 3 5 , − 3 10 , and 1 2 , respectively.…”

“…(a) The offset between q N and q c as a function of N, (b) the minimum energy gap Δ min as a function of N, and (c) the minimum energy gap Δ min as a function of the offset between q N and q c for different c with f = 1. Black solid lines show our fitting results given by equations (4)-(6). From (a) to (c), the slopes of the fitting lines are − 3 5 , − 3 10 , and 1 2 , respectively.…”

“…In recent years, researchers have shown great excitement in the study on ultracold molecule created from cold atoms or Bose-Einstein condensate (BEC) [1][2][3][4][5][6][7][8] especially on the molecular BEC formed from fermionic atoms [9][10][11][12]. The Feshbach resonance [13][14][15][16][17] is a wellaccepted experimental technique for converting ultracold atoms into ultracold molecules.…”