1. Quantum studies in LIGO Lab

2. Quantum activities in LIGO Lab
Injection of squeezed states
Demonstration on 40m prototype
Showed 2.9 dB (40%) improvement in SNR Goda et al., Nature Phys. 4, 472 (2008)
Proposed implementation on H1
Under consideration by review committee Sigg et al., LIGO-T C-D
Optical cooling and trapping of mirrors
All-optical trap for a 1 gram mirror
Minimum effective temperature of 0.8 K Corbitt et al., Phys. Rev. Lett. 98, (2007)
Optical dilution and cooling of a 1 gram mirror
Minimum effective temperature under 7 mK Corbitt et al., Phys. Rev. Lett. 99, (2007)
Active feedback cooling of the kilogram-scale LIGO mirrors
Minimum effective temperature of 1.4 mK LIGO Scientific Collaboration, in preparation

3. Quantum-enhanced interferometry
Squeezed state injection

4. Squeezing injection in 40m prototype
Laser
Prototype GW detector
SHG
Faraday isolator
The squeeze source drawn is an OPO squeezer, but it could be any other squeeze source, e.g. ponderomotive squeezer.
OPO
Homodyne Detector
Squeeze
Source
GW Signal

5. Quantum enhancement 2.9 dB or 1.4x
K. Goda, O. Miyakawa, E. E. Mikhailov, S. Saraf, R. Adhikari, K.McKenzie, R. Ward, S. Vass, A. J. Weinstein, and N. Mavalvala, Nature Physics 4, 472 (2008)

6. Proposed squeeze injection test in Enhanced LIGO circa 2010
Post-S6, pre-AdLIGO
Test performance of squeezer at ELIGO noise level
Improve SNR in shot-noise-limited band
Do no harm in other bands
Important step for readiness of squeezer for AdLIGO
Improve SNR and/or
Operate at lower power for same sensitivity

7. Advanced LIGO with squeeze injection
Radiation pressure
Shot noise

8. Mechanical oscillators in the quantum regime
Trapping and cooling mirrors

9. Reaching the quantum limit in mechanical oscillators
The goal is to measure non-classical effects with large objects like the (kilo)gram-scale mirrors
The main challenge  thermally driven mechanical fluctuations
Need to freeze out thermal fluctuations Zero-point fluctuations remain
One measure of quantumness is the thermal occupation number
Want N  1
Colder oscillator
Stiffer oscillator

10. Cooling using optical forces
Mechanical forces introduce thermal noise
Optical (or other ‘cold’) forces needed
Optical trapping and cooling
Radiation pressure of a detuned cavity provides restoring and damping forces
Restoring force  trap
Damping force  cool
Key ingredients
Light, movable mirrors
High laser power
Low noise performance to ensure mirror responds primarily to radiation pressure

11. Experimental cavity setup
10%
90%
5 W
Optical fibers
1 gram mirror
Coil/magnet pairs
for actuation (x5)‏

12. An all-optical trap for a 1 gram mirror
Stiffer than diamond
Increasing subcarrier detuning
Stable Optical Spring
T. Corbitt, Y. Chen, E. Innerhofer, H. Müller-Ebhardt, D. Ottaway, H. Rehbein, D. Sigg, S. Whitcomb, C. Wipf and N. Mavalvala, Phys. Rev. Lett 98, (2007)

13. Cooling the kilogram scale mirrors of Initial LIGO
Teff = 1.4 mK N = 234 T0/Teff = 2 x 108
Mr ~ 2.7 kg ~ 1026 atoms
Wosc = 2 p x 0.7 Hz
LIGO Scientific Collaboration

14. Activities of the LAAC

15. LIGO Academic Advisory Council
The LIGO Academic Advisory Council is charged with advising the LIGO Executive Director and Directorate on issues related to education of all students and post-docs who are participating in LIGO and to provide oversight of the quality of the education they receive through their participation in LIGO
Formed in Spring 2006
Committee
Nergis Mavalvala, MIT (Chair)
Rana Adhikari, Caltech
Nelson Christenson, Carleton College
Ex-officio members
Jay Marx, Caltech
Albert Lazzarini, Caltech
Dave Reitze, University of Florida
Student/post-doc liaisons
Evan Goetz, U. Michigan
Sam Waldman, Caltech

16. LAAC activities Maintain web site and wiki
Provide online educational resources
Thorne’s famous Ph207 lectures
Weinstein’s REU lecture series for undergraduates
Buonanno’s SLAC summer school lecture series
Links to LIGO document center
Links to workshops and summer schools and seminar series
And much more…
Administer LIGO fellowship for outstanding students to spend one year at a LIGO Observatory
Annual competition leading to two fellowships
Supplemental stipend ($5000)
Travel funds
Maintain database of graduate students within the LSC
Student thesis topics maintained by faculty advisors
Individual student wikis maintained by each student
Host annual town hall style meeting for students and postdocs

17. Recent “graduates” Doctoral students Masters students Postdocs
Joseph Betzweiser (2007) postdoc at Caltech
Thomas Corbitt (2008) postdoc at MIT
Keisuke Goda (2007) postdoc at UCLA
Lisa Goggin (2008) postdoc at UWM
Masters students
Brett Shapiro (2007)
Gautier Brunet (2007)
A. Stochino* (2007)
I. Taurasi* (2007)
Postdocs
Rana Adhikari faculty at Caltech
Duncan Brown faculty at Syracuse Univ.
Vuk Mandic faculty at U. Minnesota
Peter Shawhan faculty at U. Maryland
Sam Waldman staff scientist at MIT
Several undergraduate theses
* Degree granting institution not Caltech or MIT