Resonant Dipolar Collisions of Ultracold Molecules Induced by Microwave Dressing

Yan, Zoe; Park, Jee Woo; Ni, Yiqi; Loh, Huanqian; Will, Sebastian; Karman, Tijs; Zwierlein, Martin

doi:10.1103/physrevlett.125.063401

Cited by 46 publications

(48 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Using the state-of-the-art experimental methods described earlier in this Review, collisions have been studied in ensembles of gases at temperatures on the order of a few hundreds of nK in systems including KRb [137][138][139] , NaLi 140 , triplet Rb 2 141 , Li 2 142 , NaRb 143,144 , RbCs 81 , NaK + K 145 and NaK 146 . For all these systems of trapped ultracold molecules, fast collisional trap-loss rates have been observed.…”

Section: Reactions In the Ultracold Regime Below 1 Mkmentioning

confidence: 99%

Towards chemistry at absolute zero

Heazlewood¹,

Softley

2021

Nat Rev Chem

View full text Add to dashboard Cite

The prospect of cooling matter down to temperatures that are close to the absolute zero raises intriguing questions about how chemical reactivity changes under these extreme conditions. Although some types of chemical reaction still occur at 1 µK, they can no longer adhere to the conventional picture of reactants passing over an activation energy barrier to become products. Indeed at ultracold temperatures, the system enters a fully quantum regime, and quantum mechanics replaces the classical picture of colliding particles. In this Review, we discuss recent experimental and theoretical developments that allow us to explore chemical reactions at temperatures that range from 10 K to 500 nK. Although the field is still in its infancy, exceptional control has already been demonstrated over reactivity at low temperatures.ultracold temperatures, the classical description of the collision of particles needs to be replaced with a quantum description and the picture of a ball rolling over a hill needs to be replaced by that of a wave propagating across a barrier.The quantum regime is a physical regime in which our basic understanding of how chemical processes happen, in terms of molecules bumping into each other and breaking and remaking bonds, needs to be challenged. Strictly speaking, the dynamical system of moving and colliding molecules needs to be described as a superposition of partial waves, the components of which represent the different angular momentum states associated with the relative motion of the colliding particles. As the temperature is lowered, the system moves towards a regime in which it can be described by just a few quantised collisional angular momentum states (and, ultimately, just a single state). We denote the collisions as 's-wave' or 'p-wave' collisions (known as the partial-wave description) to represent those with zero or one unit of collisional angular momentum, respectively. Furthermore, in the quantum regime the population of molecular quantum states is distributed over just a few rovibrational states and ultimately collapses to a single quantum state at the lowest temperatures (under conditions of thermal equilibrium). At low temperatures, quantum effects on the rate coefficient and other properties of the reaction, such as collision energy resonances, quantum reflection and geometric phase (described in detail in the 'Reactions in the ultracold regime' section), are most likely to be observable. This is in contrast to what we observe at room temperature, where we understand the overall rate of a process to be an average of the behaviours of individual collisions of molecules with vastly varying sets of quantum numbers and a distribution of energies.When the temperature reaches sub-µK, the translational wavelength typically exceeds the average separation of molecules in the sample, even for a low density gas, and ultimately the system may enter the regime of quantum degeneracy (for example, bosonic particles that form a Bose-Einstein condensate, in which all particles are in the same quan...

show abstract

Section: Reactions In the Ultracold Regime Below 1 Mkmentioning

confidence: 99%

Towards chemistry at absolute zero

Heazlewood¹,

Softley

2021

Nat Rev Chem

View full text Add to dashboard Cite

show abstract

“…Note that the sign of the interaction energy is inverted compared to the interaction between two regular dipoles with dipole moment d eff . At intermediate range, the dipole-dipole interaction dominates, so that the molecules orient themselves with respect to the intermolecular axis, rather than along the rotating electric field [38]. The reorientation is made possible by contributions of the spectator states |0 .…”

Section: Microwave Shielding and Dipolar Elastic Collisionsmentioning

confidence: 99%

Evaporation of microwave-shielded polar molecules to quantum degeneracy

Schindewolf,

Bause,

Chen

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Ultracold polar molecules offer strong electric dipole moments and rich internal structure, which makes them ideal building blocks to explore exotic quantum matter [1-8], implement novel quantum information schemes [9][10][11], or test fundamental symmetries of nature [12]. Realizing their full potential requires cooling interacting molecular gases deeply into the quantum degenerate regime. However, the complexity of molecules which makes their collisions intrinsically unstable at the short range, even for nonreactive molecules [13][14][15][16][17][18], has so far prevented the cooling to quantum degeneracy in three dimensions. Here, we demonstrate evaporative cooling of a three-dimensional gas of fermionic sodium-potassium molecules to well below the Fermi temperature using microwave shielding. The molecules are protected from reaching short range with a repulsive barrier engineered by coupling rotational states with a blue-detuned circularly polarized microwave. The microwave dressing induces strong tunable dipolar interactions between the molecules, leading to high elastic collision rates that can exceed the inelastic ones by at least a factor of 460. This large elastic-toinelastic collision ratio allows us to cool the molecular gas down to 21 nanokelvin, corresponding to 0.36 times the Fermi temperature. Such unprecedentedly cold and dense samples of polar molecules open the path to the exploration of novel many-body phenomena, such as the long-sought topological p-wave superfluid states of ultracold matter.

show abstract

“…III A). Furthermore, our model can be generalized to more complete Rydberg atom models and more complex systems [58][59][60][61][62][63][64][65][66][67][68], and can also be implemented on other experimental platforms [69,70].…”

Section: Introductionmentioning

confidence: 99%

Non-Hermitian dynamics and $\mathcal{PT}$-symmetry breaking in interacting mesoscopic Rydberg platforms

Lourenço,

Higgins,

Zhang

et al. 2021

Preprint

View full text Add to dashboard Cite

We simulate the dissipative dynamics of a mesoscopic system of long-range interacting particles which can be mapped into non-Hermitian spin models with a PT symmetry. We find rich PTphase diagrams with PT -symmetric and PT -broken phases. The dynamical regimes can be further enriched by modulating tunable parameters of the system. We outline how the PT symmetries of such systems may be probed by studying their dynamics. We note that systems of Rydberg atoms and systems of Rydberg ions with strong dipolar interactions are particularly well suited for such studies. We show that for realistic parameters, long-range interactions allow the emergence of new PT -symmetric regions, generating new PT -phase transitions. In addition, such PT -symmetry phase transitions are found by changing the Rydberg atoms configurations. We monitor the transitions by accessing the populations of the Rydberg states. Their dynamics display oscillatory or exponential dependence in each phase.

show abstract

Resonant Dipolar Collisions of Ultracold Molecules Induced by Microwave Dressing

Cited by 46 publications

References 53 publications

Towards chemistry at absolute zero

Towards chemistry at absolute zero

Evaporation of microwave-shielded polar molecules to quantum degeneracy

Non-Hermitian dynamics and $\mathcal{PT}$-symmetry breaking in interacting mesoscopic Rydberg platforms

Contact Info

Product

Resources

About