Atom-molecule conversion in a periodically driven spin-boson model

Yi, Sangyong; Kim, Sang Wook

doi:10.1103/physreva.93.013616

Cited by 4 publications

(4 citation statements)

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“…For the sake of complementarity, we also consider the semiclassical dynamics of the system. According to references [47,48], we introduce two quantities L and K to define b = 1 √ 2 (L + iK) with {L, K} = 1. We normalize L, K, and 2 and the dynamical equations are…”

Section: Entanglement Entropy and Many-body Dynamicsmentioning

confidence: 99%

Quantum phase transition of a modified spin-boson model

Qin¹,

Li²

2022

J. Phys. A: Math. Theor.

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We adopt a modified spin-boson model to investigate the quantum phase transition in an ultracold atom-molecule conversion system involving moleculemolecule interaction. We explore the properties of ground state, entanglement entropy, and many-body dynamics, which confirm that the system exhibits a second-order phase transition from a pure atom phase to a mixed atom-molecule phase when the energy detuning is below a critical value. We obtain three scaling laws and the corresponding two critical exponents to characterize the phase transition. In particular, we discuss the effects of both the speed of ground-state dynamical evolution and the strength of molecular interaction on the phase transition. The adiabatic evolution condition is obtained as well. Our results show that the molecular interaction can greatly reduce the upper bound of the adiabatic condition, which provides a theoretical basis for easier observation of the phase transition in experiments.

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Section: Entanglement Entropy and Many-body Dynamicsmentioning

confidence: 99%

Quantum phase transition of a modified spin-boson model

Qin¹,

Li²

2022

J. Phys. A: Math. Theor.

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“…Combined with established cooling and trapping techniques [15,16], this opens up opportunities to explore new fundamental physics [17][18][19][20][21], controlled chemistry [22][23][24][25][26] and the quantum simulation of complex many-body systems [27][28][29][30].A key parameter by which the dynamics of the spin-Boson model are characterized is the atom-molecule coupling coefficient. The coupling coefficient determines the time scale of the Landau-Zener (LZ) transition [4,31], and many-body dynamics [10,11,[32][33][34][35][36][37] of the atom-molecule system. Understanding the coupling coefficient therefore allows control of the molecular dynamics, including pathways to adiabaticity, and is also crucial for ultracold quantum chemistry.…”

mentioning

confidence: 99%

“…A key parameter by which the dynamics of the spin-Boson model are characterized is the atom-molecule coupling coefficient. The coupling coefficient determines the time scale of the Landau-Zener (LZ) transition [4,31], and many-body dynamics [10,11,[32][33][34][35][36][37] of the atom-molecule system. Understanding the coupling coefficient therefore allows control of the molecular dynamics, including pathways to adiabaticity, and is also crucial for ultracold quantum chemistry.…”

mentioning

confidence: 99%

Observation of collectivity enhanced magnetoassociation of ⁶Li in the quantum degenerate regime

et al. 2022

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The association process of Feshbach molecules is well described by a Landau–Zener (LZ) transition above the Fermi temperature, such that two-body physics dominates the dynamics. However, using 6Li atoms and the associated Feshbach resonance at B r = 834.1 G, we observe an enhancement of the atom–molecule coupling as the fermionic atoms reach degeneracy, demonstrating the importance of many-body coherence not captured by the conventional LZ model. In the experiment, we apply a linear association ramp ranging from adiabatic to non-equilibrium molecule association for various temperatures. We develop a theoretical model that explains the temperature dependence of the atom–molecule coupling. Furthermore, we characterize this dependence experimentally and extract the atom–molecule coupling coefficient as a function of temperature, finding qualitative agreement between our model and experimental results. In addition, we simulate the dynamics of molecular association during a nonlinear field ramp. We find that, in the non-equilibrium regime, molecular association efficiency can be enhanced by sweeping the magnetic field cubically with time. Accurate measurement of the atom–molecule coupling coefficient is important for both theoretical and experimental studies of molecular association and many-body collective dynamics.

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“…Many theoretical works have shown that the coupling coefficient depends on the magnetic moment of the atom, s-wave scattering length and volume of the gas [2,29]. It determines the time scale of the Landau-Zener transition [30,31], and many-body dynamics [27,28,[32][33][34][35][36] of the atom-molecule system. At zerotemperature, it was shown that the effective atom-molecule coupling coefficient becomes collective and depends on N (N to be the number of total atoms in general), i.e.…”

mentioning

confidence: 99%

Enhanced magnetoassociation of $^6$Li in the quantum degenerate regime

Naniyil,

Zhou,

Simmonds

et al. 2021

Preprint

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The association process of Feshbach molecules is well described by a Landau-Zener transition while above the Fermi temperature, such that two-body physics dominates the dynamics. However, using 6 Li atoms and the associated Feshbach resonance at B r = 834.1G, we observe an enhancement of the atom-molecule coupling as the Fermionic atoms reach degeneracy, demonstrating the importance of many-body coherence not captured by the conventional Landau-Zener model. For this we apply a linear association ramp ranging from adiabatic to non-equilibrium molecule association for various temperatures. We develop a theoretical model that explains the temperature dependence of the atom-molecule coupling. Furthermore, we characterize this dependence experimentally and extract the atom-molecule coupling coefficient as a function of temperature, finding qualitative agreement between our model and experimental results. Accurate measurement of this coupling coefficient is important for both theoretical and experimental studies of atom-molecule association dynamics.

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Atom-molecule conversion in a periodically driven spin-boson model

Cited by 4 publications

References 50 publications

Quantum phase transition of a modified spin-boson model

Quantum phase transition of a modified spin-boson model

Observation of collectivity enhanced magnetoassociation of ⁶Li in the quantum degenerate regime

Enhanced magnetoassociation of $^6$Li in the quantum degenerate regime

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Atom-molecule conversion in a periodically driven spin-boson model

Cited by 4 publications

References 50 publications

Quantum phase transition of a modified spin-boson model

Quantum phase transition of a modified spin-boson model

Observation of collectivity enhanced magnetoassociation of 6Li in the quantum degenerate regime

Enhanced magnetoassociation of $^6$Li in the quantum degenerate regime

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Product

Resources

About

Observation of collectivity enhanced magnetoassociation of ⁶Li in the quantum degenerate regime