Warren JohnsonJohnson

Professor of Physics

Ph.D., 1974 - Rutgers University

Louisiana State University
Department of Physics & Astronomy
271-B Nicholson Hall, Tower Dr.
Baton Rouge, LA 70803-4001
Research Home Page

Research Interests

Experimental Low Temperature Physics

My research is focused on experimental work that will ultimately make observational gravitational astronomy a reality.

Analyzing the data in an optimal way for our antenna ALLEGRO has proven to require significant work in time series analysis. Our algorithm is efficient, and satisfies an optimization criterion for burst sources of gravitational waves. This antenna, after many years of development by all the members of the group, has achieved a very low level of background (or non-thermal) excitation, a condition necessary for detecting rare and ephemeral events, like the gravitational collapse of a supernova.

Steve Merkowitz and I have invented a method (the "TIGA") for making full use of a spherically shaped antenna, which will not only have a larger cross-section, but will also determine the direction to the source, and will also have equal sensitivity in all directions. The TIGA (for Truncated Icosahedral Gravitational Antenna) is really a choice of resonant transducer location, which we have shown can be used to measure all the components of the gravitational tensor wave at once. Both a national (TIGA) and an international (OMEGA) collaboration have been formed for the purpose of building a set of such spherical detectors.

There is a ongoing effort within our laboratory to realize the many technical improvements needed to reach the full potential of a new generation of cryogenic transducer used to measure the vibration amplitude of the antenna. If this work is successful, we will recapture the lead in antenna sensitivity.

A few years ago I spent time identifying a suitable site near Baton Rouge for the LIGO national laboratory, which is now under construction, and scheduled to start taking data in the year 2000. We expect our group to expand significantly, and become a major participant in the experiments done at this site.

Current and Select Publications

  • P. Astone, et al., by IGEC-2 Collaboration, "Results of the IGEC02 search for gravitational wave bursts during 2005," submitted to Phys. Rev. D(2007).
    e-Print: arXiv:0705.0688 [gr-qc]


  • B. Abbott, et al., by LIGO Scientific Collaboration, "Upper limits on gravitational wave emission from 78 radio pulsars," Phys. Rev. D 76, 042001 (2007).
    e-Print: gr-qc/0702039


  • B. Abbott, et al., by LIGO Scientific Collaboration, "Searching for a Stochastic Background of Gravitational Waves with LIGO," Astrophys. J.659, 918-930 (2007).
    e-Print: astro-ph/0608606


  • B. Abbott, et al., by LIGO Scientific Collaboration, "Joint LIGO and TAMA300 search for gravitational waves from inspiralling neutron star binaries," Phys. Rev. D 73, 102002 (2006).
    e-Print: gr-qc/0512078


  • B. Abbott., et al., by LIGO Scientific Collaboration, "Search for gravitational-wave bursts in LIGO's third science run," to appear in the proceedings of 6th Edoardo Amaldi Conference on Gravitational Waves (Amaldi6), Kise Nago, Okinawa, Japan, 20-24 June 2005, Class. Quant. Grav. 23, S29-S39 (2006).
    e-Print: gr-qc/0511146


  • M.P. McHugh, D. McNeese, W.W. Johnson, W.O. Hamilton, J. Hanson, P. Miller, D. Nettles, J. Weaver, P. Zhang, I.S. Heng, "Calibration of the ALLEGRO resonant detector," prepared for 9th Annual Gravitational Wave Data Analysis Workshop (GWDAW9), Annecy, France, 15-18 December 2004, Class. Quant. Grav. 22, S965-S973 (2005).