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A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms.

Huo MX, Nie W, Hutchinson DA, Kwek LC - Sci Rep (2014)

Bottom Line: Correspondingly, interference effects will play a role in transport.As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells.The scheme requires only standard optical access, and is robust to weak particle interactions.

View Article: PubMed Central - PubMed

Affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543.

ABSTRACT
Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a "hairline" solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions.

No MeSH data available.


Related in: MedlinePlus

The time evolution of particle distributions for particles hopping around a loop formed by LG beams in a 2D square lattice with 40 × 40 sites.At time t = 0 as shown in (a), the particles are distributed around one site. The screenshots at time  are given for the system under an Abelian U(1) (b) or a non-Abelian SU(2) ((c) and (d)) gauge field. The particle densities are represented by the percentages of particle numbers to the total number of the initially prepared Bose-Einstein condensate. While a destructive interference always occurs around the opposite site in the Abelian field case (b), a nonvanishing charge wave density occurs everywhere in (c) and spin waves appear in (d) with red- and blue-colored components, where the red-color (blue-color) component has a constructive (destructive) interference at the opposite side and a destructive (constructive) interference at its two neighboring area. Movies of the time evolution are available in the supplementary materials.
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f4: The time evolution of particle distributions for particles hopping around a loop formed by LG beams in a 2D square lattice with 40 × 40 sites.At time t = 0 as shown in (a), the particles are distributed around one site. The screenshots at time are given for the system under an Abelian U(1) (b) or a non-Abelian SU(2) ((c) and (d)) gauge field. The particle densities are represented by the percentages of particle numbers to the total number of the initially prepared Bose-Einstein condensate. While a destructive interference always occurs around the opposite site in the Abelian field case (b), a nonvanishing charge wave density occurs everywhere in (c) and spin waves appear in (d) with red- and blue-colored components, where the red-color (blue-color) component has a constructive (destructive) interference at the opposite side and a destructive (constructive) interference at its two neighboring area. Movies of the time evolution are available in the supplementary materials.

Mentions: To see the interference patterns, we load a Bose-Einstein condensate (BEC) initially away from the centre of the LG laser, as seen in the plot shown in Fig. 3(a)–(c) at t = 0 for a ring-lattice case and in Fig. 4(a) for a square-lattice case. The system is then allowed to evolve under zero, Abelian and non-Abelian gauge fields. And finally the fringe patterns are measured with time. After the initial BEC state is prepared, the LG beams are switched on. At this stage, the Hamiltonian governing the time evolution is Here we have neglected the interactions between atoms. Evolutions for weakly interacting gas are analyzed in the Methods section, where the results show that the key features of the interference patterns remain robust against a weak interaction. For an LG laser with l = 1, the accumulated phase along the circle is π. Since the atoms move along left or right path, the atoms from different paths will possess a different phase factor at the opposite site, giving a destructive interference. For an LG laser with l = 0, the phase is always zero, which resembles the system with particles moving in the absence of any gauge field. The atoms evolving along two different paths will possess the same phase factor at the opposite site, and the interference is destructive. Therefore, the interference fringes are closely related to the phase in our scheme.


A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms.

Huo MX, Nie W, Hutchinson DA, Kwek LC - Sci Rep (2014)

The time evolution of particle distributions for particles hopping around a loop formed by LG beams in a 2D square lattice with 40 × 40 sites.At time t = 0 as shown in (a), the particles are distributed around one site. The screenshots at time  are given for the system under an Abelian U(1) (b) or a non-Abelian SU(2) ((c) and (d)) gauge field. The particle densities are represented by the percentages of particle numbers to the total number of the initially prepared Bose-Einstein condensate. While a destructive interference always occurs around the opposite site in the Abelian field case (b), a nonvanishing charge wave density occurs everywhere in (c) and spin waves appear in (d) with red- and blue-colored components, where the red-color (blue-color) component has a constructive (destructive) interference at the opposite side and a destructive (constructive) interference at its two neighboring area. Movies of the time evolution are available in the supplementary materials.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126000&req=5

f4: The time evolution of particle distributions for particles hopping around a loop formed by LG beams in a 2D square lattice with 40 × 40 sites.At time t = 0 as shown in (a), the particles are distributed around one site. The screenshots at time are given for the system under an Abelian U(1) (b) or a non-Abelian SU(2) ((c) and (d)) gauge field. The particle densities are represented by the percentages of particle numbers to the total number of the initially prepared Bose-Einstein condensate. While a destructive interference always occurs around the opposite site in the Abelian field case (b), a nonvanishing charge wave density occurs everywhere in (c) and spin waves appear in (d) with red- and blue-colored components, where the red-color (blue-color) component has a constructive (destructive) interference at the opposite side and a destructive (constructive) interference at its two neighboring area. Movies of the time evolution are available in the supplementary materials.
Mentions: To see the interference patterns, we load a Bose-Einstein condensate (BEC) initially away from the centre of the LG laser, as seen in the plot shown in Fig. 3(a)–(c) at t = 0 for a ring-lattice case and in Fig. 4(a) for a square-lattice case. The system is then allowed to evolve under zero, Abelian and non-Abelian gauge fields. And finally the fringe patterns are measured with time. After the initial BEC state is prepared, the LG beams are switched on. At this stage, the Hamiltonian governing the time evolution is Here we have neglected the interactions between atoms. Evolutions for weakly interacting gas are analyzed in the Methods section, where the results show that the key features of the interference patterns remain robust against a weak interaction. For an LG laser with l = 1, the accumulated phase along the circle is π. Since the atoms move along left or right path, the atoms from different paths will possess a different phase factor at the opposite site, giving a destructive interference. For an LG laser with l = 0, the phase is always zero, which resembles the system with particles moving in the absence of any gauge field. The atoms evolving along two different paths will possess the same phase factor at the opposite site, and the interference is destructive. Therefore, the interference fringes are closely related to the phase in our scheme.

Bottom Line: Correspondingly, interference effects will play a role in transport.As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells.The scheme requires only standard optical access, and is robust to weak particle interactions.

View Article: PubMed Central - PubMed

Affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543.

ABSTRACT
Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a "hairline" solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions.

No MeSH data available.


Related in: MedlinePlus