Gravitational Wave Interferometers  

In General, Ground-Based > s.a. detection of gravitational waves [including status, other types of detectors, conceptual issues, detection news].
* Theory: For the separation between two free particles, δL / L = \(1\over2\)hTTij ni n j + O(h2).
* 2012: With Advanced LIGO and Virgo coming online, routine gravitational-wave detections are expected after 2015.
* 2015: Advanced LIGO is in its commissioning stage, preparing for scientific runs, soon to be followed by Advanced Virgo; Detections by 2018?
* 2016-02: Detection of signal from binary-black-hole coalescence announced!
* 2018-10: The US is planning the Cosmic Explorer, an L-shaped interferometer on the Earth's surface with 40-km arms (> see website).
* Polarization: 2016, Its detection will require at least three detectors (and a good signal); In practice, we may have to wait for Advanced Virgo.
@ Intros, reviews: Giazotto PRP(89); Finn gq/96 [LIGO as a community]; Barish gq/99-in; Sintes in(99)gq/00; Hough & Rowan LRR(00), update Pitkin et al LRR(11)-a1102; Robertson CQG(00); Freise & Strain LRR(10)-a0909; Bizouard & Papa CRP(13)-a1304; news at(13)may [status and plans]; Adhikari RMP(14)-a1305; Saulson 17; Feder PT(18)oct [status and plans]; Dooley et al a2103-in [and history].
@ Background: Allen & Brustein PRD(97)gq/96; Maggiore PRP(00)ap/99; Babusci & Giovannini CQG(00)ap/99, gq/99 [VIRGO].
@ Networks: Frasca & Papa IJMPD(95); Bose et al Pra(99)gq; Wen & Chen PRD(10) [angular resolution]; Schutz CQG(11) [effectiveness].
@ Detector-related topics: Sun et al PRL(96) [Sagnac interferometer]; Saulson AJP(97)jun [operation]; Cohadon et al PRL(99) + pn(99)sep [mirror cooling]; Vinet LRR(09) [optical modes and thermal issues]; Cornish PRD(09)-a0910, Melissinos & Das AJP(10)nov-a1002 [response]; Ben-Aryeh a1010 [using squeezed states and balanced homodyne detection]; Khalili PRD(11)-a1102 [Mach-Zehnder topologies for future detectors]; Graham et al PRL(13)-a1206 [based on optical atomic clocks and atom interferometry]; Hammond et al JMO(14)-a1402 [advanced technologies]; Tinto & Dhurandhar LRR(14) [time-delay interferometry]; Pang & Chen PRD(18)-a1808 [quantum interactions with gravitational waves]; Błaut CQG(19)-a1901 [gauge-independent treatment of response]; Pang & Chen PRD(19)-a1903 [measurement, radiation and decoherence]; Schubert et al a1909 [atom interferometer, between 0.3 and 5 Hz]; Jaén & Talavera a1912 [novel approach].
@ Other related topics: Buonanno & Chen CQG(01)gq/00 [and standard quantum limit]; Faraoni GRG(07)gq [correcting a misconception]; Corda IJMPD(07)gq [importance of magnetic component of waves]; Finn PRD(09)-a0810 [detailed derivation of response]; Fairhurst CQG(11)-a1010, Klimenko et al PRD(11)-a1101 [source localization]; Hild CQG(12)-a1111-proc [beyond the second generation]; Danilishin & Khalili LRR(12)-a1203 [and quantum measurement theory]; Martynov et al PRA(17)-a1702 [quantum correlation measurements]; Hagihara et al PRD(18)-a1807 [polarization, with Advanced LIGO, Advanced Virgo and KAGRA]; > s.a. physics teaching [undergraduate labs].

LIGO (Laser Interferometer Gravitational-Wave Antenna) > s.a. detection of gravitational waves [news].
* Idea: A pair of 4-km interferometers (Hanford, WA, and Livingston, LA, 10 light-ms apart), by a Caltech, MIT, ..., collaboration.
* Status: 1998, Under construction; 1999, 40-m prototype operational at Caltech, h ~ 10−19; 2000, Engineering runs; 2002, First data taking run; 2004, Three data runs completed, h ~ 10−22 Hz−1/2 at 100–300 Hz; 2006, Science runs S1–S4 completed, S5 in progress (2006–2007) with detector at design sensitivity for f > 150 Hz; 2012, Upgrade to Advanced LIGO and engineering runs, with 2nd-generation science runs expected for 2015; 2014, New interferometer installed in Livingston.
* Frequency range: f ~ 10−104 Hz, limited below by seismic noise, above by laser shot noise.
* Detection rate: Sensitive to 1 MSun binary coalescence at a few Mpc, with expected rate ~ 1/13 yr.
* Advanced LIGO: Should be able to detect inspirals out to 200 Mpc, 1–100/yr; Operation may start in 2007; 2011, Operation may start in 2015; It did, and the Collaboration reported GW150914 in 2016; 2019-04, LIGO and Virgo back on with squeezed light.
* Advanced LIGO Plus: 2019, Expected to start operating in 2024, will use squeezed light to improve sensitivity [@ news sn(19)feb].
@ General references: Finn gq/96-in [research community]; Barish & Weiss PT(99)oct [preview]; González gq/03-proc [status]; Abbott et al RPP(09)-a0711; Smith et LSC CQG(09)-a0902 [enhanced and advanced]; Waldman et LSC a1103-proc [advanced]; LSC CQG(15)-a1411, Staley et al CQG(14) [advanced]; news ns(16)apr [plans]; LSC & Virgo CQG(16) + CQG+ [detector characterization]; news sn(19)apr, focus Phys(19)dec [squeezed light].
@ Binary coalescence: LSC et Virgo PRD(10)-a1005; Abadie et al (LSC + Virgo) PRD(12), PRD(12); Aasi et al PRD(13)-a1209 [2009-2010 data]; Singer a1501-PhD [search for binary neutron star mergers]; Berry et al ApJ(15)-a1411 [ns-ns parameter estimation]; Palmese & Conselice PRL(21) [ultradwarf galaxy merger?].
@ Detections: LSC & Virgo, Abbott et al PRL(16)-a1602 + Berti Phy(16)-a1602 [GW150914]; LSC & Virgo PRD(16)-a1602 and PRL(16)-a1602; Loeb ApJL(16)-a1602 [electromagnetic counterpart?]; LSC & Virgo PRX(16)-a1606 [improved analysis]; LSC & Virgo PRL(16)-a1606 [GW151226], PRX(16)-a1606 [full results]; Abbott et al PRL(17)-a1706 + news pw(17)jun [GW170104]; news sn(17)sep [LIGO+Virgo triple detection]; news sn(19)may [status]; news sn(20)sep [intermediate-mass black hole].
@ Bursts: Weinstein for LIGO CQG(04)gq/03; Abbott et LSC PRD(05)gq [GRB030329], PRD(05)gq; LIGO CQG(07)-a0704 [4th science run]; Thorne et LSC a0706-proc; Abbott et LSC PRD(09)-a0904 [from cosmic (super)strings], PRD(09)-a0904 [high-frequency]; LSC and Virgo a1908 [supernovae, search].
@ Periodic sources: Abbott et LSC PRD(05)gq [neutron star + neutron star]; Abbott et al PRD(06) [black hole + black hole]; LSC PRD(07)gq/06 [data from S2 run]; Abbott et LSC PRD(08)-a0704, PRD(08)-a0708, PRD(08)-a0712 [data from S3 and S4 runs]; LSC PRD(09)-a0901 [data from S5 run].
@ Stochastic background: Abbott et LSC PRD(04)gq/03; LSC ApJ(07)ap/06; Abbott et LIGO + Allegro PRD(07) [cross-correlation analysis]; Fotopoulos et LSC JPCS(08)-a0801; Abadie et al PRD(12) [bounds at 600-1000 Hz].
@ Related topics: González CQG(00)gq [thermal noise in suspension]; Kocsis ApJ(13)-a1211 [SMBHs, prospects for LIGO-Virgo detections].

Other Detectors > s.a. space-based gravitational-wave interferometers.
* VIRGO: Italian-French collaboration, 3-km arms, near Pisa, very similar to LIGO; 2004, Being commissioned; 2006, Science run; 2011-2012, Advanced Virgo may start operating in 2015.
* GEO600: British-German, near Hannover; 2004, Operating, more advanced techniques than LIGO I but shorter; 2006, Beginning of continuous operation [@ news sr(06)jun]; > s.a. website.
* TAMA300: Japanese collaboration ("prototype for 3-km"), near Tokyo; 2004, Taking data since before LIGO.
* AIGO: 2006, Proposed but not accepted, its future is not certain.
* Einstein Telescope (ET): 2010, A Europen proposal for a triangle configuration of underground tunnels, three interferometers with 10-km arms cooled to around 10 K, conceived in 2008; 2020, It is currently at an advanced stage of design.
* KAGRA: 2019, An underground interferometer cooled to 20 K with 3-km-long arms in Kamioka, Japan; 2020, Recently began operations.
* LIGO-India: 2020, It is hoped that it will be operational after 2025.
@ VIRGO: Hellemans SA(03)aug; Spallicci et al CQG(05)gq/04 [advanced]; Acernese et al CQG(05)gq/04, CQG(06) [status]; Virgo CQG(08)-a0803 [search in connection with GRB 050915a]; Sengupta JPCS(10)-a0911 [LIGO-VIRGO search for coalescing binaries]; Accadia et al CQG(11) [status]; LSC & Virgo a1203 [sensitivity achieved]; Virgo Collaboration CQG(15)-a1408 [Advanced Virgo].
@ GEO600: Schutz PTPS(99)gq-in; Balasubramanian et al CQG(05)gq; Hild CQG(06) [status]; Lück et al JPCS(10)-a1004 [upgrade].
@ TAMA300: Tagoshi et al PRD(01); Ando et al PRD(05)gq/04.
@ Einstein Telescope: Bosi & Porter GRG(11)-a0910 [data analysis]; Sathyaprakash et (multi) al a1108-proc, CQG(12)-a1206-proc [scientific potential and objectives]; news livesci(18)apr; Maggiore et al JCAP(20)-a1912 [the science case]; Amann et al a2003 [site selection criteria].
@ KAGRA: KAGRA Collaboration a1710-proc [status]; Akutsu et al nAstr(19)-a1811, CQG(19)-a1901, news sn(19)jan [KAGRA]; Michimura et al a1906-MG15, PRD(20)-a2006 [improvements]; Akutsu et al a2005, PTEP-a2008, PTEP-a2009 [overview].
@ Related topics: Sato et al PRD(04)gq [LISM, underground]; Nishizawa et al PRD(08) [at 100 MHz]; Yu & Tinto GRG(11)-a1003-proc [single-arm interferometers]; Punturo & Somiya IJMPD(13)-MG13; Harms et al PRD(13)-a1308 [low-frequency terrestrial detectors]; news ns(14)feb [India]; Hu & Zhang a1707 [using weak measurements]; Park et al a1906 [stellar interferometry]; Sedda et al CQG(20)-a1908 [in the dHz range]; Liu & Gong a2001 [3D proposal]; Adya et al a2004 [Asian region, status]; news Phys(20) [high-frequency tabletop detector]; Hu & Zhang a2007 [broadband high-frequency interferometer]; Ackley et al PASA(20)-a2006 [NEMO kHz-band detector]; Saleem et al a2105 [LIGO-India].

Specific Sources and Data Analysis > s.a. gravitational-wave background [including primordial]; sources of gravitational waves.
* Binary inspirals: Because of the very low signal-to-noise ratio, the main method used is matched filtering, the comparison of data with a large set of templates developed for different parameter sets; Since the physics of binaries is simple, there are only 8 parameters (2 masses, 2 spin magnitudes, 2 spin directions), which can be reduced to 7 using overall mass scaling and 6 using statistical arguments on spins; Templates presumably need to be as accurate as O(v6); 2010, Current ones obtained using PN techniques are good enough for (possible) detection, but not for parameter estimation; For better ones, have to speed up numerical simulations considerably; To detect the weaker waves, may have to extract signal from many months of data; > s.a. numerical simulations of black holes.
* Other sources: Bursts, stochastic background, continuous sources (rotating stars, etc).
@ General references: Finn FGCS-gq/99 [data archive]; Królak gq/99; Sahay PhD(01)gq/02; Abbott et al (LIGO and Virgo) LRR(16) [observing transients].
@ Techniques: Tagliaferri et al ap/99-proc [neural networks]; Pradier et al IJMPD(00)gq-proc, PRD(01)gq/00 [filters, triggers]; Black & Gutenkunst AJP(03)apr [intro]; Hild et al CQG(10)-a0906 [proposal of xylophone configuration]; Krastev a1908 [neural networks, binary neutron star mergers].
@ Noise: Thorne & Winstein PRD(99)gq/98; Creighton PRD(99)gq; Allen et al gq/99; González SPIE(03)gq; Dolesi et al PRD(11); Thrane et al PRD(14) [correlated noise]; Powell et al CQG(15)-a1505 [classifying noise transients]; Danilishin a1903-LRR [quantum noise suppression]; > s.a. metric fluctuations.
@ Bursts: Searle et al CQG(09)-a0809 [unmodeled].
@ Binaries: Ryan PRD(97) [massive body multipoles]; Allen et al PRL(99) [bounds from 40-m prototype]; Martel AIP(99)gq, & Poisson PRD(99)gq [eccentric]; Dhurandhar & Vecchio PRD(01)gq/00; Abbott et al & Akutsu et al PRD(06) [neutron star + neutron star, LIGO+TAMA300]; Mukhopadhyay et al PRD(06)gq, PRD(09) [coherent vs coincident strategies]; Corvino et al a1203 [methods to estimate detection rates].
@ Related topics: Jaranowski et al PRD(98)gq, & Królak PRD(00)gq/99 [spinning neutron stars]; Anderson & Balasubramanian PRD(99)gq [unmodeled sources]; Yunes & Pretorius PRD(09)-a0909 [theoretical bias and post-Einsteinian framework]; Leaci JPCS(12)-a1201 [continuous wave signals].

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