LIGO-India Detecting Einstein’s Elusive Waves Opening a New Window to the Universe

1. LIGO-IndiaDetecting Einstein’s Elusive WavesOpening a New Window to the Universe IndIGO Consortium (Indian Initiative in Gravitational-wave Observations) An Indo-US joint mega-project concept proposal Version: 1R Jun 17, 2011 : TS www.gw-indigo.org

2. Space Time as a fabric Special Relativity (SR) replaced Absolute space and Absolute Time by flat 4-dimensional space-time (the normal three dimensions of space, plus a fourth dimension of time). In 1916, Albert Einstein published his famous Theory of General Relativity, his theory of gravitation consistent with SR, where gravity manifests as a curved 4-diml space-time Theory describes how space-time is affected by mass and also how energy, momentum and stresses affects space-time. Matter tells space-time how to curve, and Space-time tells matter how to move.

3. Space Time as a fabric Earth follows a “straight path” in the curved space-time caused by sun’s mass !!!

4. Beauty & Precision Einstein’s General theory of relativity is the most beautiful, as well as, successful theory of modern physics. It has matched all experimental tests of Gravitation remarkably well. Era of precision tests : GP-B,….

5. What happens when matter is in motion?

6. Einstein’s Gravity predicts • Matter in motion Space-time ripples fluctuations in space-time curvature that propagate as waves • Gravitational waves (GW) • In GR, as in EM, GW travel at the speed of light (i.e., mass-less) , are transverse and have two states of polarization. • The major qualitatively unique prediction beyond Newton’s gravity • Begs direct verification !!!

7. A Century of Waiting • Almost 100 years since Einstein predicted GW but no direct experimental confirmation a la Hertz • Two Fundamental Difference between GR and EM - Weakness of Gravitation relative to EM (10^-39) -Spin two nature of Gravitation vs Spin one of EM that forbids dipole radiation in GR • Low efficiency for conversion of mechanical energy to GW. Feeble effects of GW on a Detector • GW Hertz experiment ruled out. Only astrophysical systems involving huge masses and accelerating very strongly are potential sources of GW signals.

8. GW  Astronomy link • Astrophysical systems are sources of copious GW emission: • Typically,GW emission (0.1) >> EM radiation via Nuclear process (0.025) • Energy emitted in GW from binary >> EM radiation in the lifetime • Universe is buzzing with GW signals from cores of astrophysical events • Bursts (SN, GRB), mergers, accretion, stellar cannibalism ,… • Extremely Weak interaction, hence, has been difficult to detect directly • But also implies GW carry unscreened & uncontaminated signals

9. GW from Binary Neutron stars Pulsar companion

10. Indirect evidence for Gravity waves Nobel prize in 1993 !!! Binary pulsar systems emit gravitational waves • leads to loss of orbital energy • period speeds up 14 sec from 1975-94 • measured to ~50 msec accuracy • deviation grows quadratically with time Hulse and Taylor Results for PSR1913+16

11. Principle behind Detection of GW

12. Effect of GW on a ring of test masses Interferometer mirrors as test masses

13. Path A Path B Detecting GW with Laser Interferometer B A Difference in distance of Path A & B Interference of laser light at the detector (Photodiode)

14. Interferometry Path difference of light  phase difference Equal arms: Dark fringe The effects of gravitational waves appear as a fluctuation in the phase differences between two orthogonal light paths of an interferometer. Unequal arm: Signal in PD

15. Challenge of Direct Detection Gravitational wave is measured in terms of strain,h (change in length/original length) Gravitational waves are very weak! Expected amplitude of GW signals Measure changes of one part in thousand-billion-billion!

16. Power Recycled end test mass with Fabry-Perot Arm Cavities Light bounces back and forth along arms about 100 times Light is “recycled” about 50 times beam splitter signal LIGO Optical Configuration Michelson Interferometer input test mass Laser Courtesy: Stan Whitcomb

17. Initial LIGO Sensitivity Goal • Strain sensitivity <3x10-23 1/Hz1/2at 200 Hz • Sensor Noise • Photon Shot Noise • Residual Gas • Displacement Noise • Seismic motion • Thermal Noise • Radiation Pressure

18. LIGO and Virgo TODAY Milestone: Decades-old plans to build and operate large interferometric GW detectors now realized at several locations worldwide Experimental prowess: LIGO, VIRGO operating at predicted sensitivity!!!! • Pre-dawn GW astronomy : Unprecedented sensitivity already allows • Upper Limits on GW from a variety of Astrophysical sources. Refining theretical modelling • Improve on Spin down of Crab, Vela pulsars, • Exptally surpass Big Bang nucleosynthesis bound on Stochastic GW..

19. Laser Interferometer Gravitational-wave Observatory (LIGO) IndIGO - ACIGA meeting

20. Astrophysical Sources for Terrestrial GW Detectors • Compact binary inspiral: “chirps” • NS-NS, NS-BH, BH-BH • Supernovas or GRBs: “bursts” • GW signals observed in coincidence with EM or neutrino detectors • Pulsars in our galaxy: “periodic waves” • Rapidly rotating neutron stars • Modes of NS vibration • Cosmological: “stochastic background” ? • Probe back to the Planck time (10-43 s) • Probe phase transitions : window to force unification • Cosmological distribution of Primordial black holes Courtesy;: Stan Whitcomb

21. Using GWs to Learn about the Source an Example Over two decades, RRI involved in computation of inspiral waveforms for compact binaries & their implications and IUCAA in its Data Analysis Aspects. Can determine • Distance from the earth r • Masses of the two bodies • Orbital eccentricity e and orbital inclination i

22. Advanced LIGO • Take advantage of new technologies and on-going R&D • >> Active anti-seismic system operating to lower frequencies: • (Hannover, GEO) • >> Lower thermal noise suspensions and optics : • (GEO ) • >> Higher laser power 10 W  180 W • (Hannover group, Germany) • >> More sensitive and more flexible optical configuration: • Signal recycling (GEO) • Design: 1999 – 2010 : 10 years of high end R & D internationally. • Construction: Start 2008; Installation 2011; Completion 2015

23. “Quantum measurements” • to improve further via squeezed light: • New ground for optical technologists in India • High Potential to draw the best Indian UG students typically interested in theoretical physics into experimental science !!!

24. Tailoring the frequency response • Signal Recycling : New idea in interferometry Additional cavity formed with mirror at output Can be made resonant, or anti-resonant, for gravitational wave frequencies Allows redesigning the noise curve to create optimal band sensitive to specific astrophysical signatures

25. Schematic Optical Design of Advanced LIGO detectors Reflects International cooperation Basic nature of GW Astronomy LASER AEI, Hannover Germany Seismic isolation Suspension GEO, UK

26. Advanced LIGO Laser • Designed and contributed by Albert Einstein Institute< Germany • Higher power • 10W -> 180W • Better stability • 10x improvement in intensity and frequency stability Courtesy: Stan Whitcomb

27. Advanced LIGO Mirrors • All substrates delivered • Polishing underway • Reflective Coating process starting up • Larger size • 11 kg -> 40 kg • Smaller figure error • 0.7 nm -> 0.35 nm • Lower absorption • 2 ppm -> 0.5 ppm • Lower coating thermal noise Courtesy: Stan Whitcomb

28. Advanced LIGO Seismic Isolation • Two-stage six-degree-of-freedom active isolation • Low noise sensors, Low noise actuators • Digital control system to blend outputs of multiple sensors, tailor loop for maximum performance • Low frequency cut-off: 40 Hz -> 10 Hz Courtesy: Stan Whitcomb

29. Advanced LIGO Suspensions four stages 40 kg silica test mass 29 • UK designed and contributed test mass suspensions • Silicate bonds create quasi-monolithic pendulums using ultra-low loss fused silica fibres to suspend interferometer optics • Pendulum Q ~105 -> ~108 Suppression at 10 Hz : ? at 1 Hz : ? Courtesy: Stan Whitcomb

30. Era of Advanced LIGO detectors: 2015 • 10x sensitivity • 10x reach • 1000 volume • >> 1000 event rate • (reach beyond • nearest super-clusters) • A Day of Advanced LIGO Observation >> • A year of Initial LIGO

31. Expected Annual Coalescence Event Rates In a 95% confidence interval, rates uncertain by 3 orders of magnitude NS-NS (0.4 - 400); NS-BH (0.2 - 300) ; BH-BH (2 - 4000) yr^-1 Based on Extrapolations from observed Binary Pulsars, Stellar birth rate estimates, Population Synthesis models. Rates quoted below are mean of the distribution.

32. Scientific Payoffs • Advanced GW network sensitivity needed to observe • GW signals at monthly or even weekly rates. • Direct detection of GW probes strong field regime of gravitation •  Information about systems in which strong-field and time dependent gravitation dominates, an untested regime including non-linear self-interactions • GW detectors will uncover NEW aspects of the physics •  Sources at extreme physical conditions (eg., super nuclear density physics), relativistic motions, extreme high density, temperature and magnetic fields. • GW signals propagate un-attenuated • weak but clean signal from cores of astrophysical event where EM signal is screened by ionized matter. • Wide range of frequencies  Sensitivity over a range of astrophysical scales • To capitalize one needs a global array of GW antennas separated by continental distances to pinpoint sources in the sky and extract all the source information encoded in the GW signals

33. GEO: 0.6km VIRGO: 3km LIGO-LHO: 2km+ 4km LCGT 4km TAMA/CLIO LIGO-LLO: 4km LIGO-Australia? GW Astronomy with Intl. Network of GW Observatories 1. Detection confidence 2. Duty cycle 3. Source direction 4. Polarization info. LIGO-India ?

34. From the GWIC Strategic Roadmap for GW Science with thirty year horizon (2007) • … the first priority for ground-based gravitational wave detector development is to expand the network, adding further detectors with appropriately chosen intercontinental baselines and orientations to maximize the ability to extract source information. ….Possibilities for a detector in India (IndIGO) are being studied..

35. Indo-Aus.Meeting, Delhi, Feb 2011

36. Gravitational wave Astronomy : vit • Synergy with other major Astronomy projects • SKA -Radio : Pulsars timing, • X-ray satellite (AstroSat) : High energy physics • Gamma ray observatory: • Thirty Meter Telescope: Resolving multiple AGNs, gamma ray follow-up after GW trigger,… • LSST: Astro-transients with GW triggers. • INO:neutrino signals GWIC Roadmap Document

37. The Gravitational wave legacy Two decades of Indian contribution to the international effort for detecting GW on two significant fronts : • Seminal contributions to source modeling at RRI [Bala Iyer] and to GW data analysis at IUCAA [Sanjeev Dhurandhar] which has been internationally recognized • RRI: Indo-French collaboration for two decades to compute high accuracy waveforms for in-spiraling compact binaries from which the GW templates used in LIGO and Virgo are constructed. • IUCAA: Designing efficient data analysis algorithms involving advanced mathematical concepts. • Notable contributions include the search for binary in-spirals, hierarchical methods, coherent search with a network of detectors and the radiometric search for stochastic gravitational waves. • IUCAA has collaborated with most international GW detector groups and has been a member of the LIGO Scientific Collaboration. • At IUCAA, Tarun Souradeep with expertise in CMB data and Planck has worked to create a bridge between CMB and GW data analysis challenges.

38. Indian Gravitational wave strengths • Very good students and post-docs produced from these activities. * Leaders in GW research abroad [Sathyaprakash, Bose, Mohanty] (3) *Recently returned to faculty positions at premier Indian institutions (6) [Gopakumar, ArchanaPai, Rajesh Nayak, AnandSengupta, K.G. Arun, SanjitMitra, P. Ajith?] • Gopakumar (?) and Arun (?) : PN modeling, dynamics of CB, Ap and cosmological implications of parameter estimation • Rajesh Nayak (UTB  IISER K) , ArchanaPai (AEI  IISER T), AnandSengupta (LIGO, Caltech Delhi), SanjitMitra (JPL  IUCAA ): Extensive experience on single and multi-detector detection, hierarchical techniques, noise characterisation schemes, veto techniques for GW transients, bursts, continuous and stochastic sources, radiometric methods, … • P. Ajith (Caltech, TAPIR  ? ) …… • Sukanta Bose (Faculty UW, USA  ?) Strong Indian presences in GW Astronomy with Global detector network  broad international collaboration is the norm  relatively easy to get people back. • Close interactions with RanaAdhikari (Caltech), B.S. Sathyaprakash (Cardiff), Sukanta Bose ( WU, Pullman), SoumyaMohanty (UTB), Badri Krishnan ( AEI) … • Very supportive Intl community reflected in Intl Advisory somm of IndIGO

39. High precision and Large experiment in India • C.S. Unnikrishnan (TIFR) : involved in high precision experiments and tests • Test gravitation using most sensitive torsional balances and optical sensors. • Techniques related to precision laser spectroscopy, electronic locking, stabilization. • Ex students from this activity G.Rajalakshmi (TIFR, 3m prototype) Suresh Doravari (Caltech 40m) • Groups at BARC and RRCAT : involved in LHC • providing a variety of components and subsystems like precision magnet positioning stand jacks, superconducting correcting magnets, quench heater protection supplies and skilled manpower support for magnetic tests and measurement and help in commissioning LHC subsystems. • S.K. Shukla at RRCAT on INDUS: UHV experience. • S.B. Bhatt and Ajai Kumar at IPR on Aditya: UHV experience. • A.S. Raja Rao (ex RRCAT) : consultant on UHV • Sendhil Raja (RRCAT) : • Optical system design • laser based instrumentation, optical metrology • Large aperture optics, diffractive optics, micro-optic system design. • Anil Prabhakar IITM and Pradeep Kumar IITK (EE dept s) • Photonics, Fiber optics and communications • Characterization and testing of optical components and instruments for use in India.. • Rijuparna Chakraborty (Observatoire de la Cote d'Azur)..Adaptive Optics.. • Under consideration for postdoc in LIGO or Virgo….

40. Multi-Institutional, Multi-disciplinary Consortium (2009) • CMI, Chennai • Delhi University • IISER Kolkata • IISER Trivandrum • IIT Madras (EE) • IIT Kanpur (EE) • IUCAA • RRCAT • TIFR • RRI • IPR, Bhatt • JamiaMiliaIslamia • TezpurUniv

41. The IndIGO Consortium IndIGO Council Bala Iyer ( Chair) RRI, Bangalore Sanjeev Dhurandhar (Science) IUCAA, Pune C. S. Unnikrishnan (Experiment) TIFR, Mumbai Tarun Souradeep (Spokesperson) IUCAA, Pune Data Analysis & Theory Sanjeev Dhurandhar IUCAA Bala Iyer RRI Tarun Souradeep IUCAA Anand Sengupta Delhi University Archana Pai IISER, Thiruvananthapuram Sanjit Mitra JPL , IUCAA K G Arun Chennai Math. Inst., Chennai Rajesh Nayak IISER, Kolkata A. Gopakumar TIFR, Mumbai T R Seshadri Delhi University Patrick Dasgupta Delhi University Sanjay Jhingan Jamila Milia Islamia, Delhi L. Sriramkumar, Phys., IIT M Bhim P. Sarma Tezpur Univ . P Ajith Caltech , USA Sukanta Bose, Wash. U., USA B. S. Sathyaprakash Cardiff University, UK Soumya Mohanty UTB, Brownsville , USA Badri Krishnan Max Planck AEI, Germany Instrumentation & Experiment C. S. Unnikrishnan TIFR, Mumbai G Rajalakshmi TIFR, Mumbai P.K. Gupta RRCAT, Indore Sendhil Raja RRCAT, Indore S.K. Shukla RRCAT, Indore Raja Rao ex RRCAT, Consultant Anil Prabhakar, EE, IIT M Pradeep Kumar, EE, IIT K Ajai Kumar IPR, Bhatt S.K. Bhatt IPR, Bhatt Ranjan Gupta IUCAA, Pune Rijuparna Chakraborty, Cote d’Azur, Grasse Rana Adhikari Caltech, USA Suresh Doravari Caltech, USA Biplab Bhawal (ex LIGO)

42. 23 July 2011 Dear Bala: I am writing to invite you to attend the next meeting of the Gravitational Wave International Committee (GWIC) to present the GWIC membership application for IndIGO. This in-person meeting will give you the opportunity to interact with the members of GWIC and to answer their questions about the status and plans for IndIGO. Jim Hough (the GWIC Chair) and I have reviewed your application and believe that you have made a strong case for membership……

43. IndIGO Advisory Structure Committees: National Steering Committee: Kailash Rustagi (IIT, Mumbai) [Chair]Bala Iyer (RRI) [Coordinator]Sanjeev Dhurandhar (IUCAA) [Co-Coordinator]D.D. Bhawalkar (Quantalase, Indore)[Advisor] P.K. Kaw (IPR) Ajit Kembhavi (IUCAA) P.D. Gupta (RRCAT)J.V. Narlikar (IUCAA)G. Srinivasan International Advisory Committee Abhay Ashtekar (Penn SU)[ Chair] Rana Adhikari (LIGO, Caltech, USA) David Blair (AIGO, UWA, Australia)Adalberto Giazotto (Virgo, Italy)P.D. Gupta (Director, RRCAT, India)James Hough (GEO ; Glasgow, UK)[GWIC Chair]Kazuaki Kuroda (LCGT, Japan)Harald Lueck (GEO, Germany)Nary Man (Virgo, France)Jay Marx (LIGO, Director, USA)David McClelland (AIGO, ANU, Australia)Jesper Munch (Chair, ACIGA, Australia)B.S. Sathyaprakash (GEO, Cardiff Univ, UK)Bernard F. Schutz (GEO, Director AEI, Germany)Jean-Yves Vinet (Virgo, France)Stan Whitcomb (LIGO, Caltech, USA) Program Management Committee: C S Unnikrishnan (TIFR, Mumbai), [Chair] Bala R Iyer (RRI, Bangalore), [Coordinator] SanjeevDhurandhar (IUCAA, Pune) [Co-cordinator] TarunSouradeep (IUCAA, Pune) Bhal Chandra Joshi (NCRA, Pune) P Sreekumar (ISAC, Bangalore) P K Gupta (RRCAT, Indore) S K Shukla (RRCAT, Indore) Sendhil Raja (RRCAT, Indore)]

44. IndIGO: the goals • Provide a common umbrella to initiate and expand GW related experimental activity and training new manpower • 3m prototype detector in TIFR (funded) - Unnikrishnan • Laser expt. RRCAT, IIT M, IIT K - Sendhil Raja, Anil Prabhakar, Pradeep Kumar • Ultra High Vacuum & controls at RRCAT, IPR, BARC, ISRO, …. Shukla, Raja Rao, Bhatt, • UG summer internship at National & International GW labs & observatories. • Postgraduate IndIGO schools, specialized courses,… • Consolidated IndIGO membership of LIGO Scientific Collaboration in Advanced LIGO Proposal to create a Tier-2 data centre for LIGO Scientific Collaboration in IUCAA IUSSTF Indo-US joint Centre at IUCAA with Caltech (funded) • Major experimental science initiative in GW astronomy • Earlier Plan: Partner in LIGO-Australia(a diminishing possibility) • Advanced LIGO hardware for 1 detector to be shipped to Australia at the Gingin site, near Perth. NSF approval • Australia and International partners find funds (equiv to half the detector cost ~$140M and 10 year running cost ~$60M) within a year. • Indian partnership at 15% of Australian cost with full data rights. • Today: LIGO-India (Letter from LIGO Labs) • Advanced LIGO hardware for 1 detector to be shipped to India. • India provides suitable site and infrastructure to house the GW observatory • Site, two 4km arm length high vacuum tubes in L configuration • Indian cost ~ Rs 1000Cr The Science & technology benefit of LIGO-India is transformational

45. IndIGO 3m Prototype Detector Funded by TIFR Mumbai on compus (2010) PI: C. S. Unnikrishnan (Cost ~ INR 2.5 crore)

46. IndIGO Data Centre@IUCAA • Primary Science: Online Coherent search for GW signal from binary mergers using data from global detector network • Role of IndIGO data centre • Large Tier-2 data/compute centre for archival of g-wave data and analysis • Bring together data-analysts within the Indian gravity wave community. • Puts IndIGO on the global map for international collaboration with LIGO Science Collab. wide facility. Part of LSC participation from IndIGO • Large University sector participation via IUCAA • 200 Tflops peak capability • Storage: 4x100TB per year per interferometer. • Network: gigabit+ backbone, National Knowledge Network • Gigabit dedicatedlink to LIGO lab Caltech Courtesy: Anand Sengupta, IndIGO

47. Indo-US centre for Gravitational Physics and Astronomy APPROVED for funding (Dec 2010) • Centre of Indo-US Science and Technology Forum (IUSSTF) • Exchange program to fund mutual visits and • facilitate interaction. • Nodal centres: IUCAA , India & Caltech, US. • Institutions: • Indian: IUCAA, TIFR, IISER, DU, CMI - PI: Tarun Souradeep • US: Caltech, WSU - PI: Rana Adhikari

48. Dear Prof. Kasturirangan, 1 June 2011 In its road-map with a thirty year horizon, the Gravitational Wave International Committee (a working unit of the International Union of Pure and Applied Physics, IUPAP) has identified the expansion of the global network of gravitational wave interferometer observatories as a high priority for maximizing the scientific potential of gravitational wave observations. We are writing to you to put forward a concept proposal on behalf of LIGO Laboratory (USA) and the IndIGO Consortium, for a Joint Partnership venture to set up an Advanced gravitational wave detector at a suitable Indian site. In what follows this project is referred to as LIGO-India. The key idea is to utilize the high technology instrument components already fabricated for one of the three Advanced LIGO interferometers in an infrastructure provided by India that matches that of the US Advanced LIGO observatories. LIGO-India from LIGO LIGO-India could be operational early in the lifetime of the advanced versions of gravitational wave observatories now being installed the US (LIGO) and in Europe (Virgo and GEO) and would be of great value not only to the gravitational wave community, but to broader physics and astronomy research by launching an era of gravitational wave astronomy, including, the fundamental first direct detection of gravitational waves. As the southernmost member observatory of the global array of gravitational wave detectors, India would be unique among nations leading the scientific exploration of this new window on the universe. The present proposal promises to achieve this at a fraction of the total cost of independently establishing a fully-equipped and advanced observatory. It also offers technology that was developed over two decades of highly challenging global R&D effort that preceded the success of Initial LIGO gravitational wave detectors and the design of their advanced version.

49. LIGO-India:Why is it a good idea?for India • Has a 20 year legacy and wide recognition in the Intl. GW community with seminal contributions to Source modeling (RRI)& Data Analysis (IUCAA). High precision measurements (TIFR), Participation in LHC (RRCAT) • (Would not make it to the GWIC report, otherwise!) • AIGO/LIGO/EGO strong interest in fostering Indian community • GWIC invitation to IndIGO join as member (July 2011) • Provides an exciting challenge at an International forefront of experimental science. Can tap and siphon back the extremely good UG students trained in India. (Sole cause of `brain drain’). • 1st yr summer intern 2010  MIT for PhD • Indian experimental scientist  Postdoc at LIGO training for Adv. LIGO subsystem • Indian experimental expertise related to GW observatories will thrive and attain high levels due to LIGO-India. • Sendhil Raja, RRCAT, Anil Prabhakar, EE, IIT Madras, Pradeep Kumar, EE, IITK Photonics • Vacuum expertise with RRCAT (S.K. Shukla, A.S. Raja Rao) , IPR (S.K. Bhatt, Ajai Kumar) • Jump start direct participation in GW observations/astronomy • going beyond analysis methodology & theoretical prediction --- to full fledged participation in experiment, data acquisition, analysis and astronomy results. • For once, may be perfect time to a launch into a promising field (GW astronomy) with high end technological spinoffs well before it has obviously blossomed. Once in a generation opportunity to host an Unique International Experiment here.

50. LIGO-India:Why is it a good idea?… for the World • Strategic geographical relocation for GW astronomy • Improved duty cycle • Detection confidence • Improved Sky Coverage • Improved Location of Sources required for multi-messenger astronomy • Determine the two polarizations of GW • Potentially large science community in future • Indian demographics: youth dominated – need challenges • excellent UG education system already produces large number of trained in India find frontline research opportunity at home. • Large data analysis trained manpower and facilities exist (and being created.