We report on a class of permanent magnetic lattices for producing 2D arrays of magnetic microtraps with nonzero potential minima and variable barrier height for trapping and manipulating ultracold atoms and Bose Einstein condensates.
We propose a new class of permanent magnetic lattices on an atom chip for producing 1D and 2D periodic arrays of Ioffe-Pritchard magnetic micro-traps with variable barrier height for trapping and manipulating ultracold atoms and Bose-Einstein condensates. The barrier height of the microtraps may be varied by changing a bias magnetic field. In one of the con gurations, we show how we can go from a 1D array of 2D microtraps to a 2D array of 3D microtraps by changing the angle between two crossed arrays of parallel rectangular magnets. Furthermore, by changing the angle between the crossed arrays of magnets, the barrier heights can be varied. This suggests the possibility of performing a type of 'mechanical' BEC to Mott insulator quantum phase transition in a permanent magnetic lattice.
We report on a class of configurations of permanent magnets on an atom chip for producing 1D and 2D periodic arrays of magnetic microtraps with non-zero potential minima and variable barrier height for trapping and manipulating ultracold atoms and quantum degenerate gases. We present analytical expressions for an infinite magnetic lattice for the relevant physical quantities and compare them with our numerical results. In one of the configurations of permanent magnets, we show how it is possible by changing the angle between the crossed periodic arrays of magnets to go from a 1D array of 2D microtraps to a 2D array of 3D microtraps and thus to continuously vary the barrier heights between the microtraps.
We propose a new permanent magnetic lattice for creating periodic arrays of Ioffe-Pritchard permanent magnetic microtraps for holding and controlling ultracold atoms and Bose-Einstein condensates (BECs). Lattice can be designed on thin layer of magnetic films such as Tb6Gd10Fe80Co4. In details, we investigate single layer and two crossed layers of sawtooth magnetic patterns with thicknesses of 50 and 500nm respectively with a periodicity of 1μm. Trap depth and frequencies can be changed via an applied bias field to handle tunneling rates between lattice sites. We present analytical expressions and using numerical calculations show that this lattice has non-zero potential minima to avoid majorana spin flips. One advantage of this lattice over previous ones is that it is easier to manufacture.
We propose the use of periodic arrays of permanent magnetic films for producing magnetic lattices of microtraps for confining, manipulating and controlling small clouds of ultracold atoms and quantum degenerate gases. Using analytical expressions and numerical calculations we show that periodic arrays of magnetic films can produce one-dimensional (1D) and two-dimensional (2D) magnetic lattices with non-zero potential minima, allowing ultracold atoms to be trapped without losses due to spin flips. In particular, we show that two crossed layers of periodic arrays of parallel rectangular magnets plus bias fields, or a single layer of periodic arrays of square-shaped magnets with three different thicknesses plus bias fields, can produce 2D magnetic lattices of microtraps having non-zero potential minima and controllable trap depth. For arrays with micron-scale periodicity, the magnetic microtraps can have very large trap depths ($\sim$0.5 mK for the realistic parameters chosen for the 2D lattice) and very tight confinement.
We propose and numerically study two permanent magnetic micro-structures for creating Ioffe-Pritchard microtraps. A bias magnetic field is used to vary the depth, trap frequencies and the minimum of each microtrap. After the Bose-Einstein condensation achievement, the bias magnetic field can be slowly removed to increase the trap barrier heights for more efficiently holding the Bose-Einstein condensates. Even without the external magnetic field, it is possible to hold ultracold atoms in the microtraps. These microtraps may also be useful for single atom experiments for quantum information processing due to their very high confinement.