A Controllable Electrostatic Well for Cold Polar Molecules in Weak Field Seeking State on a Chip

doi:10.19596/j.cnki.1001-246x.7556

Abstract

Abstract: A novel electrostatic surface trap for cold polar molecules with an insulator-embedded charged ring and six charged spherical electrodes together with a bias electric field is proposed. Distributions of electric field in loading and trapping are calculated. Distance between trap center and chip surface are controlled conveniently with bias electric field and voltage applied to the ring electrode. For ND₃ molecular beam centered at ~15 m·s^-1, a loading efficiency as high as 70% is obtained. Corresponding temperature of trapped molecules is about 45 mK. As bias electric field is continued to increase, the single well splits into two identical ones. If voltages applied to spherical electrodes are changed in the meanwhile, two different wells are generated. Number ratio of molecules trapped in two wells can be adjusted. Dynamic processes of loading, trapping and splitting were simulated with classical Monte Carlo simulations.

Key words: cold polar molecules, electrostatic surface trap, Monte Carlo simulation

CLC Number:

O561

LI Shengqiang. A Controllable Electrostatic Well for Cold Polar Molecules in Weak Field Seeking State on a Chip[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2017, 34(6): 731-739.

References

[1] RETHLEM H L, BERDEN G, MEIJER G. Decelerating neutral dipolar molecules[J]. Physical Review Letters, 1999, 83(8):1558-1561.
[2] RETHLEM H L, BERDEN G, CROMPVOETS F M H, et al. Electrostatic trapping of ammonia molecules[J]. Nature, 2000, 406(6795):491-494.
[3] HUDSON E R, TICKNOR C, SAWYER B C, et al. Production of cold formaldhyde molecules for study and control of chemical reaction dynamics with hydroxyl radicals[J]. Physical Review A, 2006,73(6):063404(6).
[4] HOU S Y, LI S Q, DENG L Z, et al. Dependences of slowing results on both decelerator parameters and the new operating mode:Taking ND₃ as an example[J]. Journal of Physics B:Atomic,Molecular and Optical Physics,2013,46(4):045301(9).
[5] DENG L Z, YIN J P. Beam splitter for guided polar molecules with a Y-shaped charged wire[J]. Optics Letters, 2007,32(12):1695-1697.
[6] DENG L Z, LIANG Y, GU Z X, et al. Experimental demonstration of a controllable electrostatic molecular beam splitter[J]. Physical Review Letters, 2011,106(14):140401(4).
[7] WARK S J, OPAT G I. An electrostatic mirror for neutral polar molecules[J]. Journal of Physics B:Atomic,Molecular and Optical Physics, 1992,25(20):4229-4240.
[8] XIA Y, YIN Y L, CHEN H B, et al. Electrostatic surface guiding for cold polar molecules:Experimental demonstration[J]. Physical Review Letters, 2008,100(4):043003(4).
[9] LIU Y, YUN M, XIA Y, et al. Experimental generation of a cw cold CH₃CN molecular beam by a low-pass energy filtering[J]. Physical Chemistry Chemistry Physics, 2010,12(3):745-752.
[10] MEERAKKER S Y T, SMEETS P H M, VANHAECKE N, et al. Deceleration and electrostatic trapping of OH radicals[J].Physical Review Letters,2007,94(2):023004(4).
[11] GILLIJAMSE J J, HOEKSTRA S, MEEK S A, et al. The radiative lifetime of metastable CO(a³П,v=0)[J]. Journal of Chemical Physics, 2007,127(22):221102(4).
[12] RIEGER T, JUNGLEN T, RANGWALA S A, et al. Continuous loading of an electrostatic trap for polar molecules[J]. Physical Review Letters, 2005, 95(17):173002(4).
[13] ENGLERT B G U, MIELENZ M, SOMMER C, et al. Storage and adiabatic cooling of polar molecules in a microstructured trap[J]. Physical Review Letters, 2011, 107(26):263003(4).
[14] DEMILLE D. Quantum computation with trapped polar molecules[J]. Physical Review Letters, 2002, 88(6):067901(4).
[15] ANDRE A, DEMILLE D, DOYLE J M, et al. A coherent all-electrical interface between polar molecules and mesoscopic superconducting resonators[J]. Nature Physics, 2006,2(9):636-642.
[16] GILIJAMSE J J, HOEKSTRA S, VANDE MEERAKKER S Y T, et al. Near-threshold inelastic collisions using molecular beams with a tunable velocity[J]. Science, 2006,313(5793):1617-1620.
[17] WILLITSCH S, BELL M T, GINGELL A D, et al. Cold reactive collisions between laser-cooled ions and velocity-selected neutral molecules[J]. Physical Review Letters,2008,100(4):043203(4).
[18] OTTO R, MIKOSCH J, TRIPPEL S, et al. Nonstandard behavior of a negative ion reaction at very low temperatures[J]. Physical Review Letters,2008,101(6):063201(4).
[19] VAN DE MEERAKKER S Y T, VANHAECKE N, VAN DER LOO M P J, et al. Direct measurement of the radiative lifetime of vibrationally excited OH radicals[J]. Physical Review Letters, 2005, 95(1):013003(4).
[20] GILIJAMSE J J, HOEKSTRA S, MEEK S A, et al. The radiative lifetime of metastable CO(a³Π,v=0)[J]. Journal of Chemical Physics, 2007, 127(22):221102(4).
[21] MA H, ZHOU B, LIAO B, et al. Electrostatic surface trap for cold molecules with a charged circular wire[J]. Chinese Physics Letters, 2007, 24(5):1228-1230.
[22] WANG Q, LI S Q, HOU S Y, et al. Electrostatic surface trap for cold polar molecules on a chip[J]. Chinese Physics B, 2014, 23(1):013701(7).
[23] LI S Q, XU L, XIA Y, et al. Adiabatic cooling for cold polar molecules on a chip using a controllable high-efficiency electrostatic surface trap[J]. Chinese Physics B, 2014, 23(12):123701(7).
[24] WANG Z X, GU Z X, DENG L Z, et al. Cooling and trapping polar molecules in an electrostatic trap[J]. Chinese Physics B, 2015, 24(5):053701(5).
[25] ANDREWS M R, TOWNSEND C G, MIESNER H-J, et al. Observation of interference between two Bose condensates[J]. Science, 1997, 275(5300):637-641.
[26] INOUYE S, GUPTA S, ROSENBAND T, et al. Observation of vortex phase singularities in Bose-Einstein condensates[J]. Physical Review Letters,2001, 87(8):080402(4).
[27] MICHAEL Albiez, RUDOLF Gati, JONAS F lling, et al. Direct observation of tunneling and nonlinear self-trapping in a single Bosonic Josephson junction[J]. Physical Review Letters, 2005, 95(1):010402(4).
[28] BUGGLE Ch, LÉONARD J, VON KLITZING W, WALRAVEN J T M. Interferometric determination of the s and d-wave scattering amplitudes in ⁸⁷Rb[J]. Physical Review Letters, 2004, 93(17):173202(4).
[29] CASSETTARI Donatella, HESSMO Bjorn, FOLMAN Ron, et al. Beam splitter for guided atoms[J]. Physical Review Letters, 2000, 85(26):5483-5487.
[30] BRUGGER K, KRUGER P, LUO X, et al. Two-wire guides and traps with vertical bias fields on atom chips[J]. Physical Review A, 2005,72(2):023607(10).
[31] CASSETTARI D, CHENET A, FOLMAN R, et al. Micromanipulation of neutral atoms with nanofabricated structures[J]. Applied Physics B, 2000,70(5):721-730.
[32] REICHEL J, HANSEL W, HANSH T W. Atomic micromanipulation with magnetic surface traps[J]. Physical Review Letters, 1999,83(17):3398-3401.
[33] 唐九耀,李晓林,柯敏,等.利用原子芯片上Z形磁阱囚禁中性⁸⁷Rb原子[J].物理学报,2007,56(11):6367-6372.
[34] VELDHOVEN J, BETHLEM H L, SCHNELL M, MEIJER G. Versatile electrostatic trap[J]. Physical Review A,2006,73(6):063408(7).
[35] HOU S Y, WANG Q, DENG L Z, YIN J P. Controllable surface electrostatic velocity filter for polar molecules[J]. Journal of Physics B:Atomic,Molecular and Optical Physics, 2013,46(14):145303(8).
[36] HANSEL W, REICHEL J, HOMMELHOFF P, HANSCH T W. Trapped-atom interferometer in a magnetic microtrap[J]. Physical Review A, 2001,64(6):063607.
[37] ZHANG M, ZHANG P, CHAPMAN M S, YOU L. Controlled splitting of an atomic wave packet[J]. Physical Review Letters, 2006,97(7):070403(4).
[38] KIM S J, YU H, GANG S T, et al. Controllable asymmetric double well and ring potential on an atom chip[J]. Physical Review A, 2016, 93(3):033612(7).
[39] BERRADA T, VAN FRANK S, BUCKER R, et al. Matter-wave recombiners for trapped Bose-Einstein condensates[J]. Physical Review A, 2016,93(6):063620(10).