1. Simulations for Future Ground Based GW Detectors GWADW 2010 Kyoto, Japan

2. Matthew Evans, GWDAW 2010 What do we need simulations for anyway?  Optical System  Quantum noises  Control (length, alignment, thermal)  Mechanical System  Displacement noises (thermal, seismic, …)  Actuation of optics  Electronics  Sensing noises, actuation noise, …

3. Matthew Evans, GWDAW 2010 Tools used for iLIGO  TWIDDLE: frequency domain  SMAC: time domain  FFT code: spatial  Simulink

4. Matthew Evans, GWDAW 2010 Tools used for aLIGO (~11 years later)  Optickle: frequency (radiation pressure)  E2E: time (modular)  SIS: space (faster, more flexible)  …

5. Matthew Evans, GWDAW 2010 Establishing a code base  It may be that it is natural to repeat the same development many times, with a small improvement each time  This can be useful as writing a simulation is a great way to learn  Development process may be facilitated by a well established code base and documentation

6. Matthew Evans, GWDAW 2010 New simulations, or new simulators?  Currently we have few experts  Very busy applying simulations  Little time to write documentation  Little time to train others  (with the result that we have few experts…)  Note to simulation writers  Your time, effort and code will be forgotten  If you document and/or train it will not be wasted

7. Matthew Evans, GWDAW 2010 What do we have? What do we lack?  We have the basics covered, with one simulation or another.  We lack simulations which naturally include some combined effects  Example: parametric instabilities should arise naturally in a full opto-mechanical model  Do we need an all-inclusive simulation?  Is such a thing practical or even desirable?

8. Matthew Evans, GWDAW 2010 Simulations for 3 rd Generation Problems  Optical System  Quantum noises  Computed analytically by smart people  Can be calculated with Optickle  … but we need a system which aids design  Mechanical System  Non-linear processes (creek, creep, …)  Thermal effects and noise  Finite mass, multi-coating, stress-optic, …  Cryogenics, heat flow, material interfaces, …

9. Matthew Evans, GWDAW 2010 Simulations for 3 rd Generation Problems  Example… heat flow… noise?

10. Matthew Evans, GWDAW 2010 Simulations for 3 rd Generation Problems  Opto-mechanical System  Suspension point interferometers, limited by mechanical cross-couplings  Xylophones which share mechanical parts  Gravity Gradients  In complex, non-uniform, geological areas  In large structures (e.g., super-dome)  Cancellation with sensor array

11. Matthew Evans, GWDAW 2010 Simulations for 3 rd Generation Problems  Thermal noise limited seismic sensors  Super seismometers  Tiltometers for 1mHz-1Hz band  Particulars  Residual gas noise (squeeze films)  Charging noise, including surroundings  Parametric Instabilities  … many other things …

12. Matthew Evans, GWDAW 2010 The path ahead  Fill gaps with dedicated codes which can be incorporated into more comprehensive models as needed  Focus on making current capabilities easy to use, understand and extend  Documentation, examples, good code  Aim for more users than authors  Overlapping simulations will always exist  Let’s make sure they get better with time

13. Matthew Evans, GWDAW 2010 Enjoy Kyoto!