My broad research interest is in the field of ultracold quantum gases and the manipulation of atomic scattering properties using magnetic Feshbach resonances.
I completed my PhD in the Atomic and Molecular Physics group at Durham University working with Prof. Simon Cornish on the production of Bose-Einstein condensates with tunable atomic interactions and their application in the study of bright solitary matter-waves. Here we were able to controllably form solitary waves and observe both their classical and quantum reflection from light sheet potentials. Following my PhD, I remained in Durham as a postdoc, continuing to work on solitary waves and also spending some time working on the production of ultracold molecules.
After many happy years in Durham I finally bid farewell to the northeast and headed to Houston, Texas to join Prof. Randy Hulet at Rice University. At Rice my research focused on the use of atomic systems to explore condensed matter phenomena, in particular the search for the exotic superconducting phase FFLO which is predicted to support both superconducting and magnetic order.
On my return to the UK I took a brief detour into quantum optics, moving to Oxford to work with Prof. Ian Walmsley on a quantum enhanced microscope as part of QuantIC, the UK Quantum Technolgies hub for quantum enhanced imaging. In September 2018 I finally joined Dr Rob Smith's group to work on a new project to build an erbium BEC machine in order to study dipolar gases in novel trapping geometries.
Quantum reflection of bright solitary matter waves from a narrow attractive potential
Marchant, AL, Billam, TP, Yu, MMH, Rakonjac, A, Helm, JL, Polo, J, Weiss, C, Gardiner, SA, Cornish, SL
Bright solitons are non-dispersive wave solutions, arising in a diverse range of nonlinear, one-dimensional systems, including atomic Bose-Einstein condensates with attractive interactions. In reality, cold-atom experiments can only approach the idealized one-dimensional limit necessary for the realization of true solitons. Nevertheless, it remains possible to create bright solitary waves, the three-dimensional analogue of solitons, which maintain many of the key properties of their one-dimensional counterparts. Such solitary waves offer many potential applications and provide a rich testing ground for theoretical treatments of many-body quantum systems. Here we report the controlled formation of a bright solitary matter-wave from a Bose-Einstein condensate of (85)Rb, which is observed to propagate over a distance of ∼1.1 mm in 150 ms with no observable dispersion. We demonstrate the reflection of a solitary wave from a repulsive Gaussian barrier and contrast this to the case of a repulsive condensate, in both cases finding excellent agreement with theoretical simulations using the three-dimensional Gross-Pitaevskii equation.
Spontaneous Symmetry Breaking, Self-Trapping, and Josephson Oscillations
Bose-Einstein condensation of 85Rb by direct evaporation in an optical dipole trap
Marchant, AL, Händel, S, Hopkins, SA, Wiles, TP, Cornish, SL
Physical Review A - Atomic, Molecular, and Optical Physics
Magnetic transport apparatus for the production of ultracold atomic gases in the vicinity of a dielectric surface.
Händel, S, Marchant, AL, Wiles, TP, Hopkins, SA, Cornish, SL
Rev Sci Instrum
We present an apparatus designed for studies of atom-surface interactions using quantum degenerate gases of (85)Rb and (87)Rb in the vicinity of a room temperature dielectric surface. The surface to be investigated is a super-polished face of a glass Dove prism mounted in a glass cell under ultra-high vacuum. To maintain excellent optical access to the region surrounding the surface, magnetic transport is used to deliver ultracold atoms from a separate vacuum chamber housing the magneto-optical trap (MOT). We present a detailed description of the vacuum apparatus highlighting the novel design features; a low profile MOT chamber and the inclusion of an obstacle in the transport path. We report the characterization and optimization of the magnetic transport around the obstacle, achieving transport efficiencies of 70% with negligible heating. Finally, we demonstrate the loading of a hybrid optical-magnetic trap with (87)Rb and the creation of Bose-Einstein condensates via forced evaporative cooling close to the dielectric surface.
Guided transport of ultracold gases of rubidium up to a room-temperature dielectric surface
Marchant, AL, Händel, S, Wiles, TP, Hopkins, SA, Cornish, SL
We present a simple technique for stabilization of a laser frequency off resonance using the Faraday effect in a heated vapor cell with an applied magnetic field. In particular, we demonstrate stabilization of a 780 nm laser detuned up to 14 GHz from the (85)Rb D(2) 5(2)S(1/2) F = 2 to 5(2)P(3/2) F' = 3 transition. Control of the temperature of the vapor cell and the magnitude of the applied magnetic field allows locking ~6-14 GHz red and blue detuned from the atomic line. We obtain an rms fluctuation of 7 MHz over 1 h without stabilization of the cell temperature or magnetic field.