Stephen Powell

I am an Assistant Professor at Nordita, the Nordic Institute for Theoretical Physics, in Stockholm, Sweden.

• Email:
• Curriculum vitae
• Other contact information
• Researcher ID | Scholar profile | arXiv

Biography

• 2012– : Assistant professor, Nordita
• 2009–2012: JQI postdoctoral fellow, University of Maryland, supervisor: Sankar Das Sarma
• 2007–2009: Postdoctoral research assistant, University of Oxford, supervisor: John Chalker
• 2002–2007: Ph.D., Yale University, adviser: Subir Sachdev (thesis)
• 1998–2002: M.Phys., Christ Church, University of Oxford

Research

My research, in theoretical condensed-matter physics, concerns the diverse and remarkable phenomena that result from strong couplings between the many constituent parts of a physical system. In particular, I study frustrated magnetism and ultracold atomic gases, two areas where the elementary constituents and interactions can be understood in detail, allowing a direct appreciation of the emergent collective phenomena.

Publications

Confinement of monopoles and scaling theory near unconventional critical points, S. Powell, Phys. Rev. B 87, 064414 (2013) (also arXiv:1211.3749).

Universal monopole scaling near transitions from the Coulomb phase, S. Powell, Phys. Rev. Lett. 109, 065701 (2012) (also arXiv:1203.4564).

Order by disorder in spin-orbit coupled Bose-Einstein condensates, R. Barnett, S. Powell, T. Graß, M. Lewenstein, and S. Das Sarma, Phys. Rev. A 85, 023615 (2012) (also arXiv:1109.4945).

Higgs transitions of spin ice, S. Powell, Phys. Rev. B 84, 094437 (2011) (also arXiv:1106.6046).

Chiral Rashba spin textures in ultra-cold Fermi gases, J. D. Sau, R. Sensarma, S. Powell, I. B. Spielman, and S. Das Sarma, Phys. Rev. B 83, 140510(R) (2011) (also arXiv:1012.3170).

Bogoliubov theory of interacting bosons on a lattice in a synthetic magnetic field, S. Powell, R. Barnett, R. Sensarma, and S. Das Sarma, Phys. Rev. A 83, 013612 (2011) (also arXiv:1009.1389).

Interacting Hofstadter spectrum of atoms in an artificial gauge field, S. Powell, R. Barnett, R. Sensarma, and S. Das Sarma, Phys. Rev. Lett. 104, 255303 (2010) (also arXiv:1004.0701).

Classical to quantum mapping for an unconventional phase transition in a three-dimensional classical dimer model, S. Powell and J. T. Chalker, Phys. Rev. B 80, 134413 (2009) (also arXiv:0907.1564).

Magnetic phases and transitions of the two-species Bose-Hubbard model, S. Powell, Phys. Rev. A 79, 053614 (2009) (also arXiv:0902.1993).

SU(2)-invariant continuum theory for an unconventional phase transition in a three-dimensional classical dimer model, S. Powell and J. T. Chalker, Phys. Rev. Lett. 101, 155702 (2008) (also arXiv:0805.3698).

Classical to quantum mappings for geometrically frustrated systems: Spin-ice in a [100] field, S. Powell and J. T. Chalker, Phys. Rev. B 78, 024422 (2008) (also arXiv:0803.4204).

Spin dynamics across the superfluid-insulator transition of spinful bosons, S. Powell and S. Sachdev, Phys. Rev. A 76, 033612 (2007) (also cond-mat/0703011).

Excited state spectra at the superfluid-insulator transition out of paired condensates, S. Powell and S. Sachdev, Phys. Rev. A 75, 031601(R) (2007) (also cond-mat/0608611).

Depletion of the Bose-Einstein condensate in Bose-Fermi mixtures, S. Powell, S. Sachdev, and H. P. Büchler, Phys. Rev. B 72, 024534 (2005) (also cond-mat/0502299).

Quench dynamics across quantum critical points, K. Sengupta, S. Powell, and S. Sachdev, Phys. Rev. A 69, 053616 (2004) (also cond-mat/0311355).

Background: Close-packed dimers on a square lattice. For a large lattice with A sites, the number of allowed configurations approaches e^GA/π, where G is Catalan's constant (see, for instance, Kasteleyn and Fisher and Stephenson). [Fast|Slow|Stop]

(The dimer animation is experimental, and is known not to work on Firefox earlier than version 3 and Internet Explorer earlier than version 7. If you have any problems with it, try reloading the page first, and then please .)