Feed icon


Watt Steam Engine

On quantum scales, there are many second laws of thermodynamics

New research from UCL has uncovered additional second laws of thermodynamics which complement the ordinary second law of thermodynamics, one of the most fundamental laws of nature. These new second laws are generally not noticeable except on very small scales, at which point, they become increasingly important. More...

Published: Feb 10, 2015 11:55:53 AM

Spectrum of hot methane

Spectrum of hot methane in astronomical objects using a comprehensive computed line list

A powerful new model to detect life on planets outside of our solar system, more accurately than ever before, has been developed by researchers from UCL Physics & Astronomy and the University of New South Wales. More...

Published: Jun 18, 2014 4:54:56 PM

Quantum Phase Transitions

"Like melting an entire iceberg with a hot poker" – UCL scientists explore the strange world of quantum phase transitions

“What a curious feeling,” says Alice in Lewis Carroll’s tale, as she shrinks to a fraction of her size, and everything around her suddenly looks totally unfamiliar. Scientists too have to get used to these curious feelings when they examine matter on tiny scales and at low temperatures: all the behaviour we are used to seeing around us is turned on its head. More...

Published: May 13, 2014 4:06:57 PM



  1. T. E. Wall, A. M. Alonso, B. S. Cooper, A. Deller, S. D. Hogan and D. B. Cassidy, "Selective production of Rydberg-Stark states of positronium", Phys. Rev. Lett., 114, 173001 (2015) DOI:10.1103/PhysRevLett.114.173001


  1. T. E. Wall, D. B. Cassidy and S. D. Hogan, "Single-color two-photon spectroscopy of Rydberg states in electric fields", Phys. Rev. A, 90, 053430 (2014) DOI:10.1103/PhysRevA.90.053430
  2. P. Lancuba and S. D. Hogan, "Transmission-line decelerators for atoms in high Rydberg states", Phys. Rev. A, 90, 053420 (2014) DOI:10.1103/PhysRevA.90.053420
  3. H. Ko and S. D. Hogan, "High-field-seeking Rydberg atoms orbiting a charged wire", Phys. Rev. A89, 053410 (2014) DOI:10.1103/PhysRevA.89.053410
  4. D. B. Cassidy and S. D. Hogan, "Atom control and gravity measurements using Rydberg positronium", Int. J. Mod. Phys. Conf. Ser.30, 1460259 (2014) DOI:10.1142/S2010194514602592


  1. P. Lancuba and S. D. Hogan, "Guiding Rydberg atoms above surface-based transmission lines", Phys. Rev. A88, 043427 (2013) DOI:10.1103/PhysRevA.88.043427
  2. S. D. Hogan, "Calculated photoexcitation spectra of positronium Rydberg states",Phys. Rev. A87, 063423 (2013) DOI:10.1103/PhysRevA.87.063423
  3. S. D. Hogan, Ch. Seiler and F. Merkt, "Motional, isotope and quadratic Stark effects in Rydberg-Stark deceleration and electric trapping of H and D", J. Phys. B: At. Mol. Opt. Phys., 46, 045303 (2013) DOI:10.1088/0953-4075/46/4/045303


  1. S. D. Hogan, J. A. Agner, F. Merkt, T. Thiele, S. Filipp and A. Wallraff, "Driving Rydberg-Rydberg transitions from a co-planar microwave  waveguide", Phys. Rev. Lett. 108, 063004 (2012) DOI:10.1103/PhysRevLett.108.063004
  2. S. D. Hogan, P. Allmendinger, H. Saßmannshausen, H. Schmutz and F. Merkt, "A surface-electrode Rydberg-Stark decelerator", Phys. Rev. Lett. 108, 063008 (2012) DOI:10.1103/PhysRevLett.108.063008
  3. Ch. Seiler, S. D. Hogan and F. Merkt, "Dynamical processes in Rydberg-Stark  deceleration and trapping of atoms and molecules", Chimia 66, 208 (2012) DOI:10.2533/chimia.2012.208
  4. S. D. Hogan, "Cold atoms and molecules by Zeeman deceleration and Rydberg-Stark deceleration", Habilitation Thesis, Laboratory of Physical Chemistry, ETH Zurich (2012) [download pdf (33 MB)]


  1. S. D. Hogan, M. Motsch and F. Merkt, "Deceleration of supersonic beams using inhomogeneous electric and magnetic fields", Phys. Chem. Chem. Phys. 13, 18705 (2011) DOI:10.1039/C1CP21733J
  2. Ch. Seiler, S. D. Hogan and F. Merkt, "Trapping cold molecular hydrogen", Phys. Chem. Chem. Phys. 13, 19000 (2011) DOI:10.1039/C1CP21276A
  3. Ch. Seiler, S. D. Hogan, H. Schmutz, J. A. Agner and F. Merkt, "Collisional and radiative processes in adiabatic deceleration, deflection and off-axis trapping of a Rydberg atom beam", Phys. Rev. Lett. 106, 073003 (2011) DOI:10.1103/PhysRevLett.106.073003
  4. A. W. Wiederkehr, M. Motsch, S. D. Hogan, M. Andrist, H. Schmutz, B. Lambillotte, J. A. Agner and F. Merkt, "Multistage Zeeman deceleration of metastable neon", J. Chem. Phys. 135, 214202 (2011) DOI:10.1063/1.3662141


  1. A. W. Wiederkehr, S. D. Hogan, B. Lambillotte, M. Andrist, H. Schmutz, J. Agner, Y. Salathé and F. Merkt, "Trapping deuterium atoms", Phys. Rev. A 81, 021402(R) (2010) DOI:10.1103/PhysRevA.81.021402
  2. A. W. Wiederkehr, S. D. Hogan and F. Merkt, "Phase stability in a multistage Zeeman decelerator", Phys. Rev. A 82, 043428 (2010) DOI:10.1103/PhysRevA.82.043428


  1. S. D. Hogan, Ch. Seiler and F. Merkt, "Rydberg-state-enabled deceleration and trapping of cold molecules", Phys. Rev. Lett. 103, 123001 (2009) DOI:10.1103/PhysRevLett.103.123001
  2. S. D. Hogan and F. Merkt, "A New Perspective on the Binding Power of an Electron", ChemPhysChem 10, 2931 (2009) DOI:10.1002/cphc.200900499


  1. S. D. Hogan and F. Merkt, "Demonstration of Three-Dimensional Electrostatic Trapping of State-Selected Rydberg Atoms", Phys. Rev. Lett. 100, 043001 (2008) DOI:10.1103/PhysRevLett.100.043001
  2. S. D. Hogan, E. Vliegen, D. Sprecher, N. Vanhaecke, M. Andrist, H. Schmutz, U. Meier, B. H. Meier and F. Merkt, "Stark and Zeeman deceleration of neutral atoms and molecules" in "Laser Spectroscopy. Proceedings of the XVIII International Conference ICOLS 2007" Leo Hollberg (ed.), Jim Bergquist (ed.) and Mark Kasevich (ed.) World Scientific, Singapore, 153-166 (2008) DOI:10.1142/9789812813206_0013
  3. S. D. Hogan, A. W. Wiederkehr, M. Andrist, H. Schmutz and F. Merkt, "Slow beams of atomic hydrogen by multistage Zeeman deceleration", J. Phys. B: At. Mol. Opt. Phys. 41, 081005 (2008) DOI:10.1088/0953-4075/41/8/081005
  4. S. D. Hogan, A. W. Wiederkehr, H. Schmutz and F. Merkt, "Magnetic trapping of hydrogen after multistage Zeeman deceleration", Phys. Rev. Lett. 101, 143001 (2008) DOI:10.1103/PhysRevLett.101.143001
  5. J.-P. Connerade, S. D. Hogan, H.-P. Liu and M.-S. Zhan, "Towards a test of sting theory using Rydberg atoms", Eur. Phys. J. D 46, 431 (2008) DOI:10.1140/epjd/e2007-00335-x
  6. A. Kellerbauer, M. Amoretti, A. S. Belov, G. Bonomi, I. Boscolo, R. S. Brusa, M. Büchner, V. M. Byakov, L. Cabaret, C. Canali, C. Carraro, F. Castelli, S. Cialdi, M. de Combarieu, D. Comparat, G. Consolati, N. Djourelov, M. Doser, G. Drobychev, A. Dupasquier, G. Ferrari, P. Forget, L. Formaro, A. Gervasini, M. G. Giammarchi, S. N. Gninenko, G. Gribakin, S. D. Hogan, M. Jacquey, V. Lagomarsino, G. Manuzio, S. Mariazzi, V. A. Matveev, J. O. Meier, F. Merkt, P. Nedelec, M. K. Oberthaler, P. Pari, M. Prevedelli, F. Quasso, A. Rotondi, D. Sillou, S. V. Stepanov, H. H. Stroke, G. Testera, G. M. Tino, G. Trénec, A. Vairo, J. Vigué, H. Walters, U. Warring, S. Zavatarelli and D. S. Zvezhinskij, "Proposed antimatter gravity measurement with an antihydrogen beam", Nucl. Instr. and Meth. in Phys. Res. B 266, 351 (2008) DOI:10.1016/j.nimb.2007.12.010


  1. S. D. Hogan, D. Sprecher, M. Andrist, N. Vanhaecke and F. Merkt, "Zeeman deceleration of H and D", Phys. Rev. A 76, 023412 (2007) DOI:10.1103/PhysRevA.76.023412
  2. E. Vliegen, S. D. Hogan, H. Schmutz and F. Merkt, "Stark deceleration and trapping of hydrogen Rydberg atoms", Phys. Rev. A 76, 023405 (2007) DOI:10.1103/PhysRevA.76.023405
  3. J.-P. Connerade, S. D. Hogan, A. M. Abdulla and M. S. Zhan, "Highly excited atoms - a homage to Pierre Jacquinot", Phys. Scr. 76, C140 (2007) DOI:10.1088/0031-8949/76/4/N06
  4. S. D. Hogan and J.-P. Connerade, "On the effect of resolution on nearest-neighbour level spacings in atomic spectra", Eur. Phys. J. D 44, 47 (2007) DOI:10.1140/epjd/e2007-00165-x


  1. S. D. Hogan, "Rydberg states interacting in crossed electric and magnetic fields", PhD Thesis, Department of Physics, Imperial College London (2006)
  2. H. P. Liu, Z. G. Sun, S. D. Hogan and N. Q. Lou, "Photodissociation dynamics of CF3I investigated by two-color femtosecond laser pulses", Eur. Phys. J. D 40, 357 (2006) DOI:10.1140/epjd/e2006-00183-2


  1. S. Gundry, M. P. Anscombe, A. M. Abdulla, S. D. Hogan, E. Sali, J. W. G. Tisch, and J. P. Marangos, "Off-resonant preparation of a vibrational coherence for enhanced stimulated Raman scattering", Phys. Rev. A 72, 033824 (2005) DOI:10.1103/PhysRevA.72.033824
  2. J.-P. Connerade, S. D. Hogan and A. M. Abdulla, "Experimental investigation of atoms in crossed electric and magnetic fields", J. Phys. B: At. Mol. Opt. Phys. 38 S141 (2005) DOI:10.1088/0953-4075/38/2/011


  1. A. M. Abdulla, S. Hogan, M. S. Zhan and J.-P. Connerade, "High-lying Rydberg states of barium in crossed fields", J. Phys. B: At. Mol. Opt. Phys. 37 L147 (2004) DOI:10.1088/0953-4075/37/8/L01