Publications

2023

  • Positronium density measurements using polaritonic effects. E. Cortese, D. B. Cassidy and S. D. Liberato, Phys. Rev. A 107, 023306 (2023) DOI: 10.1103/PhysRevA.107.023306

2022

  • Positronium microwave spectroscopy using Ramsey interferometry. T. J. Babij and D. B. Cassidy, EPJ D. 76, 121 (2022) DOI: 10.1140/epjd/s10053-022-00448-w
  • Precision spectroscopy of positronium: Testing bound-state QED theory and the search for physics beyond the Standard Model. G. S. Adkins, D. B. Cassidy, J. Pérez-Ríos, Phys. Rep. 975, 1 (2022) DOI: 10.1016/j.physrep.2022.05.002

2021

  • Line-shape modelling in microwave spectroscopy of the positronium n=2 fine-structure intervals. L. A. Akopyan, T. J. Babij, K. Lakhmanskiy, D. B. Cassidy and A. Matveev, Phys. Rev. A. 104, 062810 (2021)
    DOI: 10.1103/PhysRevA.104.062810 
  • Observation of asymmetric line shapes in precision microwave spectroscopy of the positronium 2\,^3S_1 \rightarrow 2\,^3P_J \; (J=1,2) fine-structure intervals. L. Gurung, T. J. Babij, J. Pérez-Ríos, S. D. Hogan and D. B. Cassidy, Phys. Rev. A. 103, 042805 (2021) DOI:10.1103/PhysRevA.103.042805
  • Fast decay of 2\,^3S_1 positronium atoms in an MgO lined cavity. L. Gurung, T. J. Babij, and D. B. Cassidy, EPJ Techniques and Instrumentation, 8, 3 (2021) DOI:10.1140/epjti/s40485-020-00058-z

2020

  • Measurement of the annihilation decay rate of 2\,^3S_1 positronium. R. E. Sheldon, T. J. Babij, B. A. Devlin-Hill, L. Gurung and D. B. Cassidy, EPL, 132, 13001 (2020) DOI:10.1209/0295-5075/132/13001
  • Precision Microwave Spectroscopy of the Positronium n = 2 Fine Structure. L. Gurung, T. J. Babij, S. D. Hogan and D. B. Cassidy, Phys. Rev. Lett. 125, 073002 (2020) DOI:PhysRevLett.125.073002

    Associated news articles: www.sciencemag.org/news; www.sciencenews.org

  • Resonant shifts of positronium energy levels in MgO powder.  L. Gurung, B. S. Cooper, S. D. Hogan and D. B. Cassidy, Phys. Rev. A, 101, 012701 (2020) DOI:PhysRevA.101.012701

2019

  • Multiring electrostatic guide for Rydberg positronium. M. H. Rayment, L. Gurung, R. E. Sheldon, S. D. Hogan and D. B. Cassidy, Phys. Rev. A, 100, 013410 (2019) DOI:PhysRevA.100.013410
  • Positronium emission from MgO smoke nanocrystals. L. Gurung, A. M. Alonso, T. J. Babij, B. S. Cooper, A. L. Shluger and D. B. Cassidy, J. Phys. B: At. Mol. Opt. Phys. 52, 105004 (2019) DOI: 10.1088/1361-6455/ab0f06.

2018

  • State-selective electric-field ionization of Rydberg positronium. A. M. Alonso, L. Gurung, B. A. D. Sukra, S. D. Hogan and D. B. Cassidy. Phys. Rev. A, 98, 053417 (2018) DOI: 10.1103/PhysRevA.98.053417.
  • Annihilation of positronium atoms confined in mesoporous and macroporous SiO_2 films. B. S. Cooper, J. -P. Boilot, C. Corbel, F. Guillemot, L. Gurung, L. Liszkay and D. B. Cassidy. Phys. Rev. B, 97, 205302 (2018) DOI: 10.1103/PhysRevB.97.205302 .
  • Experimental progress in positronium laser physics. D. B. Cassidy. Eur. Phys. J. D, 72, 53 (2018) DOI: 10.1140/epjd/e2018-80721-y.

2017

  • Velocity selection of Rydberg positronium using a curved electrostatic guide. A. M. Alonso, B. S. Cooper, A. Deller, L. Gurung, S. D. Hogan and D. B. Cassidy. Phys. Rev. A, 95, 053409 (2017) DOI:10.1103/PhysRevA.95.053409.
  • Production of 2\,^3S_1 positronium atoms by single-photon excitation in an electric field. A. M. Alonso, S. D. Hogan and D. B. Cassidy. Phys. Rev. A 95, 033408 (2017) DOI:10.1103/PhysRevA.95.033408.

2016

  • SSPALS for atomic physics with positronium. Adam Deller, (2016) arXiv:1609.04993.
  • A CF4 based positron trap. S. Marjanović, A. Banković, D. Cassidy, B. Cooper, A. Deller, S. Dujko and Z. Lj Petrović. J. Phys. B: At. Mol. Opt. Phys. 49, 215001  (2016) DOI:10.1088/0953-4075/49/21/215001.
  • Electrostatically Guided Rydberg Positronium. A. Deller, A. M. Alonso, B. S. Cooper, S. D. Hogan, and D. B. Cassidy. Phys. Rev. Lett 117, 073202 (2016) DOI:10.1103/PhysRevLett.117.073202.
  • Measurement of Rydberg positronium fluorescence lifetimes. A. Deller, A. M. Alonso, B. S. Cooper, S. D. Hogan, and D. B. Cassidy. Phys. Rev. A 93, 062513  (2016) DOI:10.1103/PhysRevA.93.062513.
  • Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms. A. R. Swann, D. B. Cassidy, A. Deller, and G. F. Gribakin, Phys. Rev. A 93, 052712 – Published 20 May 2016 DOI:10.1103/PhysRevA.93.052712.
  • Single-shot positron annihilation lifetime spectroscopy with LYSO scintillators, A. M. Alonso, B. S. Cooper, A. Deller, and D. B. Cassidy, Nucl. Instrum. Methods Phys. Res. A  828, 163 (2016) DOI:10.1016/j.nima.2016.05.049.
  • Positronium production in cryogenic environments. B. S. Cooper, A. M. Alonso, A. Deller, L. Liszkay, and D. B. Cassidy, Phys. Rev. B 93, 125305 (2016) DOI:10.1103/PhysRevB.93.125305.
  • Positronium decay from n = 2 states in electric and magnetic fields. A. M. Alonso, B. S. Cooper, A. Deller, S. D. Hogan, and D. B. Cassidy, Phys. Rev. A 93, 012506 (2016) DOI:10.1103/PhysRevA.93.012506.

2015

  • Controlling Positronium Annihilation with Electric Fields.  A. M. Alonso, B. S. Cooper, A. Deller, S. D. Hogan and D. B. Cassidy, Phys. Rev. Lett. 115, 183401 (2015) DOI:10.1103/PhysRevLett.115.183401.
  • A trap-based pulsed positron beam optimised for positronium laser spectroscopy. B. S. Cooper, A. M. Alonso, A. Deller, T. E. Wall, and D. B. Cassidy, Rev. Sci. Instrum. 86, 103101 (2015) DOI:/10.1063/1.4931690.
  • Positronium emission and cooling in reflection and transmission from thin meso-structured silica films. S. L Andersen, D. B Cassidy, J. Chevallier, B. S. Cooper, A. Deller, T. E. Wall and U. I. Uggerhøj, J. Phys. B: At. Mol. Opt. Phys. 48, 204003 (2015) DOI:10.1088/0953-4075/48/20/204003.
  • Selective Production of Rydberg-Stark States of Positronium. T. E. Wall, A. M. Alonso, B. S. Cooper, A. Deller, S. D. Hogan, and D. B. Cassidy, Phys. Rev. Lett. 114, 173001 (2015) DOI:10.1103/PhysRevLett.114.173001.
  • Positronium emission from mesoporous silica studied by laser-enhanced time-of-flight spectroscopy. A. Deller, B. S. Cooper, T. E. Wall and D. B. Cassidy, New J. Phys. 17 043059 (2015)  DOI:10.1088/1367-2630/17/4/043059.
  • Prospects for Studies of the Free Fall and Gravitational Quantum States of Antimatter. G. Dufour, D. B. Cassidy, P. Crivelli, et al,  Advances in High Energy Physics, vol. 2015, Article ID 379642, 16 pages, (2015) DOI:10.1155/2015/379642.

2014

  • Single-color two-photon spectroscopy of Rydberg states in electric fields. T. E. Wall, D. B. Cassidy, and S. D. Hogan, Phys. Rev. A 90,  053430 (2014) DOI: 10.1103/PhysRevA.90.053430.
  • Doppler-corrected Balmer spectroscopy of Rydberg positronium. A.C.L. Jones et al, Phys. Rev. A 90, 012503 (2014) DOI: 10.1103/PhysRevA.90.012503.
  • Atom control and gravity measurements using Rydberg positronium. D. B. Cassidy and S. D. Hogan, Int. J. Mod. Phys. Conf. Ser. 30, 1460259 (2014) DOI: 10.1142/S2010194514602592.