Document from the year 2020 in the subject Physics - Optics, grade: 2, Manipal University (Department of Electronics and Communication Engineering - Manipal University Jaipur), course: Research, language: English, abstract: Magnetic traps for neutral atoms play an important role in achieving Bose-Einstein condensation (BEC) of atomic gases. The simplest way to magnetically trap atoms is to use the quadrupole field created by two coils with currents in opposite directions. In this configuration the atoms with appropriate spin state can be trapped at the middle of the coil where field is zero. For an atom in a weak-field-seeking state, atom are trapped at minima of magnetic field. The potential in a quadrupole trap grows linearly with distance from the trap center, where the magnetic field is zero. The major shortcoming of quadrupole traps is that cold atoms are removed from the trap due to Majorana flips at the trap center. This problem was overcome in time-averaged orbiting potential (TOP) traps and in Ioffe-Pritchard (IP) traps, which are both successfully used in current BEC experiments. However, the TOP trap is somewhat limited in its applications due to the low trap depth and the peculiarities arising from the rotating field. On the other hand, Ioffe traps require large currents and typically dissipate several kilowatts of power, which causes cooling, stabilization, and switching problems. Quadrupole Ioffe configuration (QUIC) trap consists of two identical quadrupole coils and one Ioffe coil, which is conical type, which operated at low currents and has no problem of spin flips at trap center because of finite field at the center. This trap dissipates less power, which simplifies the heat removal. If the current through the Ioffe coil is ramped from zero to its final value, the trapping potential smoothly changes from a quadrupole to an Ioffe potential. A current Iq through the quadrupole coils produces a spherical quadrupole trap in the center of the two coils. The trap is converted into the Ioffe configuration by turning on the current Iioffe through the Ioffe coil. With increasing current Iioffe the magnetic zero of the quadrupole is shifted towards the Ioffe coil. At certain value of Iioffe, the trap produce a non-vanishing offset field B0 and exhibit a harmonic variation of the potential close to the trap minimum. The advantage of the QUIC trap is that much lower currents are required and the coils can remain outside the vacuum. The disadvantage of this design is that the field minimum has moved toward the Ioffe Coil. This place a limit on optical access to the BEC QUIC trap generates a small finite magnetic field at the minimum of potential energy for BEC.

Auteur

Dr. Prashant Povel Dwivedi received a Bachelor of Science (Honours), Master of Science in Physics from Institute of Science, Banaras Hindu University, Varanasi, India, Master of Technology in Laser Science and Applications, Devi Ahilya Vishwavidyalaya/ Raja Rammana centre for advanced Technology (RRCAT), Indore, India, and PhD in Advanced Optical Physics from Pusan National University (PNU), South Korea. During his doctorate he worked on the fabrication of periodically poled lithium niobate crystals and its quality evaluation. Dr. Dwivedi is currently working as Assistant Professor (Senior Scale) in Electronics and Communication Engineering Department, Manipal University, Jaipur, Rajasthan, India. His research interest is broadly in the area of Optics and photonics, Ultra cold Atoms and Molecules, He have more than 5 years of experience in the research fields of fabrication of Quasi-phase matching (QPM) devices and Evaluation of Domain Randomness by Diffraction-Noise Measurement in PNU, South Korea and more than 2 years of experience in the build a cold atom system with a two-dimensional magneto-optical trap (MOT) for atomic beam and subsequent three dimensional MOT in Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan, also Design and Development of QUIC Trap for Bose Einstein Condensation Set-Up in RRCAT, Indore, India . He have earned valuable skills in cutting-edge, experimental QPM fabrication techniques and have been associated with MOT facilities in the South Korea, Taiwan and India. He have been consistently publishing my research in top journals and conferences including Optics Express, Applied Physics B, Journal of the optical society of Korea and SPIE. His achievements include several awards and honors recognizing the quality of my research, presentation skill, and future potential as a young researcher.