光阱中~(87)Rb原子玻色-爱因斯坦凝聚态的实验研究
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摘要
本文主要包括两方面的内容,一是光阱中玻色-爱因斯坦凝聚态(BEC)的实验研究,这是本人在研究生期间最主要的工作。首先介绍了BEC的一些基础理论和知识,对激光冷却原子的机制(多普勒冷却机制和偏振梯度冷却机制)做了简单的论述,然后详细介绍了我们实验上实现BEC的各个系统和步骤。第二部分是为实现Feshbach共振进行的实验准备,制作了能够承受大电流的磁场线圈,以及通过一个积分反馈电路来控制磁场稳定度。
In this paper, we mainly introduce two works. One is that we creat Bose-Einstein condensate (BEC) in a optical dipole trap, which is my primary work during my graduate student. Firstly, an overview of the background knowledge of BEC is given. Then the basic theories and our experiment of BEC are introduced detailedly. The second one is my preparation for the experiment of Feshbach resonance. We make compact Helmholtz coils which can endure high current and produce a strong magnetic field. And the magnetic field can be stabilized by controlling the stability of the current. We use a negative feedback circuit to control the stability of the current up to 1*10~(-5).
In this paper, we mainly introduce two works. One is that we creat Bose-Einstein condensate (BEC) in a optical dipole trap, which is my primary work during my graduate student. Firstly, an overview of the background knowledge of BEC is given. Then the basic theories and our experiment of BEC are introduced detailedly. The second one is my preparation for the experiment of Feshbach resonance. We make compact Helmholtz coils which can endure high current and produce a strong magnetic field. And the magnetic field can be stabilized by controlling the stability of the current. We use a negative feedback circuit to control the stability of the current up to 1*10~(-5).
引文
[1] F. Dalfovo, S. Giorgini, L. P. Pitaevskii, and S. Stringari. Theory of Bose-Einstein Condensation in trapped gases. Rev. Mod. Phys. (1999) 71, 463-512.
[2] A. J. Leggett. Bose-Einstein condensation in the alkali gases: Some fundamental concepts. Rev. Mod. Phys. (2001) 73, 307-356.
[3] T. Hansch, and A. Schawlow. Cooling of gases by laser radiation. Opt. Commun. (1975) 13, 68.
[4] M. H. Anderson, J. R. Ensher, M. R. Matthews, C. E. Wieman, and E. A. Cornell. Observation of Bose-Einstein condensation in a dilute atomic vapor. Science (1995) 269, 198-201.
[5] K. B. Davis, M. O. Mewes, M. R. Andrews, N. J. van Druten, D. S. Durfee, D. M. Kurn, and W. Ketterle. Bose-Einstein condensation in a gas of sodium atoms. Phys. Rev. Lett. (1995) 75, 3969-3973.
[6] C. C. Bradley, C. A. Sackett, J. J. Tollett, and R. G. Hulet. Evidence of Bose-Einstein condensation in an atomic gas with attractive interaction. Phys. Rev. Lett. (1995) 75, 1687-1690.
[7] W. Hansel et al., Bose-Einstein condensation on a microelectronic chip. Nature. (2001) 413, 498.
[8] T. Fernholz et al., Fully permanent magnet atom chip for Bose-Einstein condensation. Phys. Rev. A. (2008) 77, 033409.
[9] M. D. Barrett, J. A. Sauer, and M. S. Chapman. All-Optical Formation of an Atomic Bose-Einstein Condensate. Phys. Rev. Lett. (2001) 87, 010404.
[10] A. F. D. Comparat, G. Stern, E. Dimova, B. Laburthe Tolra and P. Pillet. Optimized production of large Bose Einstein Condensates.
[11] Y. J. Lin et al., Rapid production of Rb-87 Bose-Einstein condensates in a combined magnetic and optical potential. Phys. Rev. A. (2009) 79, 063631.
[12] M. Greiner, C. A. Regal, and D. S. Jin. Emergence of a molecular Bose-Einstein condensate from a Fermi gas. Nature. (2003) 426, 537-540.
[13] C. Chin, M. Bartenstein, A. Altmeyer, S. Riedl, S. Jochim, J. Hecker Denschlag, and R. Grimm. Observation of the Paring Gap in a Strongly Interacting Fermi Gas. Science. (2004) 305, 1128-1131.
[14] M. Greiner et al., Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms. Nature 415, 39 (2002).
[15] R. Jordens et al., A Mott insulator of fermionic atoms in an optical lattice. Nature 455, 204 (2008).
[16] T. Weber, J. Herbig, M. Mark, H-C. N?gerl, and R. Grimm. Bose-Einstein condensation of cesium. Science (2003) 299, 232-235.
[17] K. Xu, T. Mukaiyama, J. R. Abo-Shaeer, J. K. Chin, D. Miller, and W. Ketterle, Formation of Quantum-Degenerate Sodium Molecules. Phys. Rev. Lett. (2003) 91, 210402.
[18] Ketterle W, Durfee DS, Stamper-Kurn DM. Making, probing and understandingBose-Einstein condensates. arXivorg: cond-mat/9904034. 1999.
[19] K. Huang. Statistical Mechanics (Viley, New York, 1963).
[20] Pethick CJ, Smith H. Bose-Einstein condensation in dilute gases: Cambridge 2002.
[21]陈帅。87Rb原子玻色-爱因斯坦凝聚的实验研究。北京大学博士研究生学位论文。2004年10月。
[22] Lett PD, Watts RN, Westbrook CI, Phillips WD, Gould PL, Metcalf HJ. Observation of Atoms Laser Cooled below the Doppler Limit. Phys. Rev. Lett. 1988, 61(2),169.
[23] Shevy Y, Weiss DS, Ungar PJ, Chu S. Bimodal speed distributions in laser-cooled atoms. Phys. Rev. Lett. 1989, 62(10), 1118.
[24] Dalibard J, Cohen-Tannoudji C. Laser cooling below the Doppler limit by polarization gradients: simple theoretical models. J. Opt. Soc. Am. B. 1989, 6, 2023.
[25] Ungar PJ, Weiss DS, Riis E, Chu S. Optical molasses and multilevel atoms: theory. J. OPT. Soc. Am. B. 1987, 6, 2058-82.
[26] Shengwang Du. Atom-chip Bose-Einstein condensation in a portable vacuum cell. Dissertation for PhD of University of Colorado. 2005.
[27] Rudolf Grimm, Matthias Weidemuller, Yurii B. Ovchinnikov. Optical dipole traps for neutral atoms. arXiv: physics/9902072.
[28] Luiten OJ, Reynolds MW, Walraven JTM. Kinetic theory of the evaporative cooling of a trapped gas. Phys. Rev. A. 1996, 53(1), 381.
[29] Y. Castin and R. Dum. Bose-Einstein Condensates in Time Dependent Traps. Phys. Rev. Lett. 1996, 77, 5315-5319.
[30] Wolfgang Ketterle, Martin W. Zwierlein. Making, probing and understanding ultracold Fermi gases. Arxiv: 0801. 2500v1[cond-mat. Other] 16 Jan 2008.
[31] Cheng Chin, Rudolf Grimm, Paul Julienne, et al. Feshbach resonances in ultracold gases. Rev. Mod. Phys. 2010, 82, 1225-1286.
[32] C. Klempt, T. Henninger, O. Topic, et al. 40K-87Rb Feshbach resonances: Modeling the interatomic potential. Phys. Rev. A., 2007, 76: 020701(R).
[2] A. J. Leggett. Bose-Einstein condensation in the alkali gases: Some fundamental concepts. Rev. Mod. Phys. (2001) 73, 307-356.
[3] T. Hansch, and A. Schawlow. Cooling of gases by laser radiation. Opt. Commun. (1975) 13, 68.
[4] M. H. Anderson, J. R. Ensher, M. R. Matthews, C. E. Wieman, and E. A. Cornell. Observation of Bose-Einstein condensation in a dilute atomic vapor. Science (1995) 269, 198-201.
[5] K. B. Davis, M. O. Mewes, M. R. Andrews, N. J. van Druten, D. S. Durfee, D. M. Kurn, and W. Ketterle. Bose-Einstein condensation in a gas of sodium atoms. Phys. Rev. Lett. (1995) 75, 3969-3973.
[6] C. C. Bradley, C. A. Sackett, J. J. Tollett, and R. G. Hulet. Evidence of Bose-Einstein condensation in an atomic gas with attractive interaction. Phys. Rev. Lett. (1995) 75, 1687-1690.
[7] W. Hansel et al., Bose-Einstein condensation on a microelectronic chip. Nature. (2001) 413, 498.
[8] T. Fernholz et al., Fully permanent magnet atom chip for Bose-Einstein condensation. Phys. Rev. A. (2008) 77, 033409.
[9] M. D. Barrett, J. A. Sauer, and M. S. Chapman. All-Optical Formation of an Atomic Bose-Einstein Condensate. Phys. Rev. Lett. (2001) 87, 010404.
[10] A. F. D. Comparat, G. Stern, E. Dimova, B. Laburthe Tolra and P. Pillet. Optimized production of large Bose Einstein Condensates.
[11] Y. J. Lin et al., Rapid production of Rb-87 Bose-Einstein condensates in a combined magnetic and optical potential. Phys. Rev. A. (2009) 79, 063631.
[12] M. Greiner, C. A. Regal, and D. S. Jin. Emergence of a molecular Bose-Einstein condensate from a Fermi gas. Nature. (2003) 426, 537-540.
[13] C. Chin, M. Bartenstein, A. Altmeyer, S. Riedl, S. Jochim, J. Hecker Denschlag, and R. Grimm. Observation of the Paring Gap in a Strongly Interacting Fermi Gas. Science. (2004) 305, 1128-1131.
[14] M. Greiner et al., Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms. Nature 415, 39 (2002).
[15] R. Jordens et al., A Mott insulator of fermionic atoms in an optical lattice. Nature 455, 204 (2008).
[16] T. Weber, J. Herbig, M. Mark, H-C. N?gerl, and R. Grimm. Bose-Einstein condensation of cesium. Science (2003) 299, 232-235.
[17] K. Xu, T. Mukaiyama, J. R. Abo-Shaeer, J. K. Chin, D. Miller, and W. Ketterle, Formation of Quantum-Degenerate Sodium Molecules. Phys. Rev. Lett. (2003) 91, 210402.
[18] Ketterle W, Durfee DS, Stamper-Kurn DM. Making, probing and understandingBose-Einstein condensates. arXivorg: cond-mat/9904034. 1999.
[19] K. Huang. Statistical Mechanics (Viley, New York, 1963).
[20] Pethick CJ, Smith H. Bose-Einstein condensation in dilute gases: Cambridge 2002.
[21]陈帅。87Rb原子玻色-爱因斯坦凝聚的实验研究。北京大学博士研究生学位论文。2004年10月。
[22] Lett PD, Watts RN, Westbrook CI, Phillips WD, Gould PL, Metcalf HJ. Observation of Atoms Laser Cooled below the Doppler Limit. Phys. Rev. Lett. 1988, 61(2),169.
[23] Shevy Y, Weiss DS, Ungar PJ, Chu S. Bimodal speed distributions in laser-cooled atoms. Phys. Rev. Lett. 1989, 62(10), 1118.
[24] Dalibard J, Cohen-Tannoudji C. Laser cooling below the Doppler limit by polarization gradients: simple theoretical models. J. Opt. Soc. Am. B. 1989, 6, 2023.
[25] Ungar PJ, Weiss DS, Riis E, Chu S. Optical molasses and multilevel atoms: theory. J. OPT. Soc. Am. B. 1987, 6, 2058-82.
[26] Shengwang Du. Atom-chip Bose-Einstein condensation in a portable vacuum cell. Dissertation for PhD of University of Colorado. 2005.
[27] Rudolf Grimm, Matthias Weidemuller, Yurii B. Ovchinnikov. Optical dipole traps for neutral atoms. arXiv: physics/9902072.
[28] Luiten OJ, Reynolds MW, Walraven JTM. Kinetic theory of the evaporative cooling of a trapped gas. Phys. Rev. A. 1996, 53(1), 381.
[29] Y. Castin and R. Dum. Bose-Einstein Condensates in Time Dependent Traps. Phys. Rev. Lett. 1996, 77, 5315-5319.
[30] Wolfgang Ketterle, Martin W. Zwierlein. Making, probing and understanding ultracold Fermi gases. Arxiv: 0801. 2500v1[cond-mat. Other] 16 Jan 2008.
[31] Cheng Chin, Rudolf Grimm, Paul Julienne, et al. Feshbach resonances in ultracold gases. Rev. Mod. Phys. 2010, 82, 1225-1286.
[32] C. Klempt, T. Henninger, O. Topic, et al. 40K-87Rb Feshbach resonances: Modeling the interatomic potential. Phys. Rev. A., 2007, 76: 020701(R).