Pendular trapping conditions for ultracold polar molecules enforced by external electric fields

Li, Ming; Petrov, A. N.; Makrides, Constantinos; Tiesinga, Eite; Kotochigova, Svetlana

doi:10.1103/physreva.95.063422

Cited by 11 publications

(17 citation statements)

References 31 publications

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“…Although there are 32 sublevels for each (N, M N ), split by the nuclear Zeeman interaction, the hyperfine coupling no longer has a significant impact on the level structure for states that are predominantly M N = 0. This implies that a simpler Hamiltonian can be used to explain the internal structure; for this we drop H hf and H Zeeman from (1) to leave a simpler hindered-rotor Hamiltonian [31,89,90]. The eigenstates of this simpler system do not depend on the nuclear spin degrees of freedom and can be constructed from the spherical harmonics alone [31,89],…”

Section: B Application To Rbcsmentioning

confidence: 99%

Controlling the ac Stark effect of RbCs with dc electric and magnetic fields

et al. 2020

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We investigate the effects of static electric and magnetic fields on the differential ac Stark shifts for microwave transitions in ultracold bosonic 87 Rb 133 Cs molecules, for light of wavelength λ = 1064 nm. Near this wavelength we observe unexpected two-photon transitions that may cause trap loss. We measure the ac Stark effect in external magnetic and electric fields, using microwave spectroscopy of the first rotational transition. We quantify the isotropic and anisotropic parts of the molecular polarizability at this wavelength. We demonstrate that a modest electric field can decouple the nuclear spins from the rotational angular momentum, greatly simplifying the ac Stark effect. We use this simplification to control the ac Stark shift using the polarization angle of the trapping laser.

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Section: B Application To Rbcsmentioning

confidence: 99%

Controlling the ac Stark effect of RbCs with dc electric and magnetic fields

et al. 2020

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“…In order to model the energies of all relevant rotational hyperfine levels in various external field set-ups, we follow the formalism of Ref. [29] and the references therein. In the rovibronic ground state manifold the effective Hamiltonian includes interactions from rotation, hyperfine, Zeeman, ac and dc Stark effects.…”

Section: Ac-stark Maps Of the Rotational Transitionmentioning

confidence: 99%

“…The coherence time in such a magic trap is limited by the intensity dependence of the molecular polarizabil-ity, which originates from the coupling between rotation, nuclear spins, and the trapping light field. It has been suggested to apply large magnetic [28] or electric fields [29] to reduce these couplings and thus simplify the polarizabilities of the involved states.…”

mentioning

confidence: 99%

Extending Rotational Coherence of Interacting Polar Molecules in a Spin-Decoupled Magic Trap

Seeßelberg

Luo

et al. 2018

Phys. Rev. Lett.

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Superpositions of rotational states in polar molecules induce strong, long-range dipolar interactions. Here we extend the rotational coherence by nearly one order of magnitude to 8.7(6) ms in a dilute gas of polar 23 Na 40 K molecules in an optical trap. We demonstrate spin-decoupled magic trapping, which cancels first-order and reduces second-order differential light shifts. The latter is achieved with a dc electric field that decouples nuclear spin, rotation, and trapping light field. We observe density-dependent coherence times, which can be explained by dipolar interactions in the bulk gas.Interacting particles with long coherence times are a key ingredient for entanglement generation and quantum engineering. Cold and ultracold polar molecules [1][2][3][4][5][6][7][8][9][10][11] are promising systems for exploring such quantum manybody physics with long-range interactions [12,13] due to their strong and tunable electric dipole moment and long single-particle lifetime [14,15]. The manipulation of their rich internal degrees of freedom has been studied for different molecular species [16][17][18][19]. First observations include ultracold chemistry and collisions [20,21]. Nuclear spin states in the rovibronic ground state further promise exciting prospects for quantum computation due to their extremely long coherence times [22].Rotation is a particularly appealing degree of freedom for molecules because it is directly linked to their dipolar interactions. It can be manipulated by microwave (MW) fields and superpositions of rotational states with opposite parity exhibit an oscillating dipole moment with a magnitude close to the permanent electric dipole moment d 0 . Consequently, using rotating polar molecules has been proposed for quantum computation [23], to emulate exotic spin models [24] or to create topological superfluids [25].In order to make use of the rotational transition dipole in a spatially inhomogeneous optical trap, the coupling of the rotation to the trap field needs to be canceled. To first order this may be achieved by choosing an appropriate angle between the angular momentum of the molecule and the trapping field polarization ε [26] or a special trap light intensity [19] such that the differential polarizability between rotational ground and excited states is canceled. The trap is then referred to as "magic". Coherence times of about 1 ms have been achieved in bulk gases of polar molecules using these techniques [19,27]. However, this is much shorter than the dipolar interaction time, preventing observation of many-body spin dynamics.The coherence time in such a magic trap is limited by the intensity dependence of the molecular polarizabil-ity, which originates from the coupling between rotation, nuclear spins, and the trapping light field. It has been suggested to apply large magnetic [28] or electric fields [29] to reduce these couplings and thus simplify the polarizabilities of the involved states.In this work, we realize a spin-decoupled magic trap, i.e. a magic polarization angle trap wit...

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“…Whereas either adiabatic interactions [26][27][28][29][30][31][32][33][34][35][36][37][38] or their impulsive, non-adiabatic counterparts [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] have received much attention, interactions with finiteduration pulses have been scarce [54][55][56]. It is the last that are the focus of the present study.…”

Section: Introductionmentioning

confidence: 94%

Quantum dynamics of a polar rotor acted upon by an electric rectangular pulse of variable duration

2021

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As demonstrated in our previous work [J. Chem. Phys. 149, 174109 (2018)], the kinetic energy imparted to a quantum rotor by a non-resonant electromagnetic pulse with a Gaussian temporal profile exhibits quasi-periodic drops as a function of the pulse duration. Herein, we show that this behaviour can be reproduced with a simple waveform, namely a rectangular electric pulse of variable duration, and examine, both numerically and analytically, its causes. Our analysis reveals that the drops result from the oscillating populations that make up the wavepacket created by the pulse and that they are necessarily accompanied by drops in the orientation and by a restoration of the pre-pulse alignment of the rotor. Handy analytic formulae are derived that allow to predict the pulse durations leading to diminished kinetic energy transfer and orientation. Experimental scenarios are discussed where the phenomenon could be utilised or be detrimental.

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Pendular trapping conditions for ultracold polar molecules enforced by external electric fields

Cited by 11 publications

References 31 publications

Controlling the ac Stark effect of RbCs with dc electric and magnetic fields

Controlling the ac Stark effect of RbCs with dc electric and magnetic fields

Extending Rotational Coherence of Interacting Polar Molecules in a Spin-Decoupled Magic Trap

Quantum dynamics of a polar rotor acted upon by an electric rectangular pulse of variable duration

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