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We demonstrate the direct loading of cold atoms into a microchip 2-mm Z-trap, where the evaporative cooling can be performed efficiently, from a macroscopic quadrupole magnetic trap with a high loading efficiency. The macroscopic quadrupole magnetic trap potential is designed to be moveable by controlling the currents of the two pairs of anti-Helmholtz coils. The cold atoms are initially prepared in a standard six-beam magneto-optical trap and loaded into the macroscopic quadrupole magnetic trap, and then transported to the atom chip surface by moving the macroscopic trap potential. By means of a three-dimensional absorption imaging system, we are able to optimize the position alignment of the atom cloud in the macroscopic trap and the microchip Z-shaped wire. Consequently, with a proper magnetic transfer scheme, we load the cold atoms into the microchip Z-trap directly and efficiently. The loading efficiency is measured to be about 50%. This approach can be used to generate appropriate ultracold atoms sources, for example, for a magnetically guided atom interferometer based on atom chip.

We propose a new miniature Bose-Einstein condensate (BEC) system based on a transparent atom chip with a compact external coil structure. A standard six-beam macroscopic magneto-optical trap (MOT) is able to be created near the chip surface due to the chip's transparency. A novel wire pattern consisting of a double-z wire and a z-shaped wire is designed on the transparent atom chip. With a vertical bias magnetic field, the double-z wire can create the quadrupole magnetic field of an intermediate chip MOT, which is suitable for transporting atoms from the macroscopic MOT to the chip z-wire trap efficiently. The compact external coil structure is designed with a rectangular frameless geometry consisting of only four coil pairs and its volume is less than 0.3 liters. The maximum system power consumption during the BEC generation procedure is about 45 W. The miniature system is evaluated, and about 3 x 10(6) atoms can be loaded into the chip z-wire trap. The miniature chip BEC system has the advantages of small volume and low power consumption, and it has great potential for practical applications of BEC.

This work experimentally demonstrates a new method of optimizing the transport of cold atoms via modulating the velocity profile imposed on a magnetic quadrupole trap. The trap velocity and corresponding modulation are controlled by varying the currents of two pairs of anti-Helmholtz coils. Cold 87Rb atoms are transported in a non-adiabatic regime over 22 mm in 200 ms. For the transported atoms their final-vibration amplitude dependences of modulation period number, depth, and initial phase are investigated. With modulation period n=5, modulation depth K=0.55, and initial phase =0, cold atom clouds with more atom numbers, smaller final-vibration amplitude, and lower temperature are efficiently transported. Theoretical analysis and numerical simulation are also provided, which are in good agreement with experimental results.

The standard model of particle physics predicts a complex structure of decay modes for hadrons, which opens up an avenue for observing the internal forces governing the decay dynamics. In this paper, we present the decay modes of hadrons as a network in which the nodes are particles and directed links are pointing from the mother particles to daughter particles. Using the database of decay modes collected from the Particle Data Group, we try to unveil the topological structure and possible intrinsic nature of hadron decays in the light of recent investigations of complex networks. We study distributions of the numbers of daughter and mother particles, and explore scaling laws that may govern the underlying decay structure of the system. We find that it is a small-world network with symmetrical structure. We also study the influence of constraints arising from conservation laws on the network structure, and our analysis suggests that the constraints of conservations of momentum-energy, charge, lepton number and baryon number play important roles in the topology of the decay network. Finally, we classify the hadrons into communities according to their quark component, and uncover the relationship between the particle roles and connection patterns in the communities.