Elena Losero - INDICO @ INAF
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Elena Losero e.losero@inrim.it EMPIR-17FUN01 - BeCOMe EMPIR-17FUN06 - SIQUST Li ght-matter interplay for optical metrol ogy beyond the classical spatial Si ngle-photon s ources as new res olution limits qua ntum standards COST Action MP1405 NATO Project FQXi Project FET Open project - Pathos The Time Machine Factory 2019 – Torino – September 22-25
Our team QUANTUM OPTICS GROUP at INRIM, Torino (ITALY) Siva Elena Paolo Ivo P. Marco Christian S. Tobias Ulrik L. Pradyumna Losero Traina Degiovanni Genovese Jacobsen Gehring Andersen Ivano Ruo- Massimo Stefano Olivares Berchera Zucco (Univ. Milano) The Time Machine Factory 2019 – Torino – September 22-25
Introduction Systems of two interferometers Theory can be interesting for testing Planck [PRL 110, 213601 (2013), scale physics PRA 92, 053821 (2015)] Can quantum light enhance the sensitivity of a system of two interferometers? Experiment Quantum light Paper under review can help in [arXiv:1810.13386] enhancing the sensitivity of one interferometer The Time Machine Factory 2019 – Torino – September 22-25
New theories for Planck scale Several heuristic QG theories predicts non-commutativity of position variables at Planck scale: Systems of two interferometers can be interesting for testing Planck = 5.40 × 10 −44 s scale physics Fundamental space-time uncertainty principle called “holographic noise (HN)” [C. Hogan, Arxiv: 1204.5948; C. Hogan, PRD 85, 064007 (2012)]: How can we have experimental access to this noise? The Time Machine Factory 2019 – Torino – September 22-25
Looking for “macroscopic” effects In a Michelson interferometer holographic noise accumulates as a random walk (bounded by a single light round trip, = 2 / ) becoming detectable for L sufficiently high. Systems of two interferometers can be interesting for testing Planck 1 d scale physics 2 d [C. Hogan, Arxiv: 1204.5948; C. Hogan, PRD 85, 064007 (2012)] HN spectrum: for L ∼ 40 m the maximum is in the MHz region High sensitivity is required. How it can be distinguished by other noise sources? nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Correlated interferometers for HN HN should be correlated in the two interferometers if they are in the same space time volume Systems of two [C. Hogan,interferometers Arxiv: 1204.5948; C. Hogan, PRD 85, 064007 (2012)] can be interesting for Even testingifPlanck the HN is hidden by the photon shot noise in one interferometer, it could emerge in the scale physics cross-correlation between two of them. Shot noise is uncorrelated and therefore is statistically washed away. HOLOMETER HN lower bounded to 10−20 m/ Hz in the MHz region of the spectrum after 165 h of acquisition. = 2 KW = 40 m nome, date e luogo della conferenza [PRL 117, 111102 (2016)] The Time Machine Factory 2019 – Torino – September 22-25
Other applications of correlated interferometry Fundamental noise at the Planck scale in quantum gravity model Systems of two interferometers [First Measurements of High Frequency Cross-Spectra from a Pair of Large Michelson Interferometers, PRL 117, can be 111102 (2016)] interesting for [PRD 85, 064007 (2012)] testing Planck scale physics Stochastic Gravitational Wave Background (10-36 to 10-32 seconds after the Big Bang, whereas the Cosmic Micro-wave Background was produced 300,000 years later) [Search for a Stochastic Background of 100-MHz GW with Laser Interferometers, PRL 101, 101101 (2008)] [Upper limits on a stochastic GW background using LIGO and Virgo interferometers, PRD 85, 122001 (2012)] Traces of primordial blackholes [MHz gravitational wave constraints with decameter Michelson interferometers, PRD 95, 063002 (2017)] nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Quantum light in one interferometer (theory) Vacuum Squeezed states of light are injected from the antisymmetric port. 1 2 Ψ = 0 = exp ( ∗ 2 − + ) = e 2 sq + + = 2 Δ Δ − + d = 2 coh Δ Δ Quantum light Uncertainty can on help one in of the quadrature is below the vacuum enhancing the −2 sensitivity of Var < Var 2 ∆ = one 2 interferometer Var < Var Vacuum squeezed states of light from can enhance the phase sensitivity of an interferometer [Caves, PRD 23, 1693 (1981)] nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Squeezed light experimentally works! The use of vacuum squeezed states is now exploited in several gravitational wave detectors 2.15 ± 0.05 dB Quantum enhancement [R. Schnabel et al., Nature Commun. 1, 121 (2010), Ligo, Nature Phys. 7, 962 (2011)] And many others The Time Machine Factory 2019 – Torino – September 22-25
Coming back to our question… Systems of two Systems of two interferometers interferometers can be can be interesting for interesting for testing Plancktesting Planck scale physicsscale physics Can quantum light enhance the sensitivity of a system of two interferometers? Quantum light Quantum light can help in can help in enhancing the enhancing the sensitivity ofsensitivity of one one interferometer interferometer nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Quantum light in two interferometers [PRL 110, 213601 (2013), PRA 92, 053821 (2015)] Two independent squeezed states Two mode squeezing (Twin Beam) Ψ 1 2 = 2 00 1 2 = exp ( ∗ 1 2 − + + 1 2 ) 00 Ψ 1 2 = 1 1 2 2 0 1 ⊗ 0 2 ∞ 1 , 1 2 1+ 1+ Quadrature squeezing =0 • Photon number entanglement: −2 1 ∆2 1 = 1 = 1e 1 Ψ 1 − 2 Ψ 1 2 =0 2 Δ2 1 − 2 = 0 −2 2 • Quadrature correlations: 2 ∆ 2 = 2 = 2 e 2 2 −2 2 ∆ ( 1 − 2 ) = = e 2 The Time Machine Factory 2019 – Torino – September 22-25
Quantum light in two interferometers 1 2 [PRL 110, 213601 (2013), PRA 92, 053821 (2015)] Two independent squeezed states Two mode squeezing (Twin Beam) ∆2(∆ 1 ∆ 2) × < ∆2(∆ 1∆ 2) ∆2( 1 − 2) < ∆2( 1 − 2) ∆2(∆ 1 ∆ 2) × < ∆2(∆ 1 ∆ 2) Correlated signal can emerge better from the Correlated signals are deleted in the subtraction, noise. uncorrelated signals can emerge. Obs: the quantity C considered is different in the two cases nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Theoretical results • 0 central working phase Uncertainty (normalized to SNL) • detection efficiency • number of photon of quantum light • number of photon of coherent state Ph Numb Quadrature Green region is for TWB advantage ENTANG correlations with respect to double squeezing TWB leads to disruptive advantages! = (cos Τ2) 2 ≈ 1 …Unfortunately this regime is extremely challenging for real experiments [PRL 110, 213601 (2013), PRA 92, 053821 (2015)] nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Experimental set-up: The classical part ▪ Read-out AS port operated close to the dark fringe (LIGO, HOLOMETER) M ▪ 2-D Power recycling cavity M 90% reflectivity (gain =10) 0.92 ▪ We focus around 13.5 MHz, being the system shot-noise M MI 1 limited at this frequency PRM BS Laser M MI 2 1064 nm BS PRM BS I1 Isolator I2 Isolator Antisymmetric port, [arXiv:1810.13386] classically unused The Time Machine Factory 2019 – Torino – September 22-25
Experimental set-up: Quantum states injected ▪ Two possibility explored M M ▪ Data are differently analyzed in the two cases M BS MI 1 PRM ▪ Instead of a real TWB we consider a single squeezed beam split by a BS: they present Laser M MI 2 PRM BS BS same correlation between quadrature Isolator I1 I2 Isolator Quantum states injected Squeezed Squeezed Vacuum Vacuum Squeezed Vacuum I1⨉ I2 I1- I2 [arXiv:1810.13386] The Time Machine Factory 2019 – Torino – September 22-25
Set-up details Adder lC - lD lC PZT “CARM” M PID EOM LO 20 MHz Mixer PD PD M PRM PZT lC + lD Adder Laser Beam 1064 nm Focusing BS EOM Isolator PRM LO 7.6 MHz Isolator “DARM” lD -1 PID PD Mixer LO “Phase” Beam Squeezer 37.22 MHz PID Focusing Mixer PZT EOM (36.7 MHz) The Time Machine Factory 2019 – Torino – September 22-25
Experimental results (time domain) • Correlated white noise injected (about 1/5 of the shot noise level) • About 3dB of squeezing in each interferometer • The cross correlation peak emerges at the increasing of the measurement time • Noise floor reduced by SQ injection nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Experimental results (time domain) Time measurement reduction • SNR improves with the usual statistical scaling samples • Correlated white noise injected (about 1/5 of the shot noise level) • SNR is twice when •squeezing is injected About 3dB of squeezing in each interferometer • 4 times • Thereduction in the measurement cross correlation time peak emerges at demonstrated the increasing of the measurement time • Noise floor reduced by SQ injection nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Experimental results (frequency domain) 3 dB 10 dB N spectra =1000 • A correlated white noise is injected (amplitude around 1/5 of the photon shot noise of each MI), its detection is easier when squeezing is injected • CLSD reduces the shot-noise contribution nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Experimental results (frequency domain) Plateau corresponding to the amplitude of the signal The CLSDs scale as spectra−1/4 The maximum sensitivity measured is 3 ⋅ 10−17 m/√Hz nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Experimental results (time domain) Var( 1 − 2) (dB) 2.5 dB • Quadrature correlation leads to noise reduction in the difference of the photon currents Δ2 1 − 2 < SNL = 1 + 2 • 2.5 dB of squeezing measured in the output subtraction nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Experimental results (time domain) 0.3 dB Var( 1 − 2) (dB) 1 dB • Uncorrelated white noise injected • The noise emerge better when TWB is used • This enhancement might be applied to identify uncorrelated noise sources, such as scattering or unwanted resonances nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Experimental results (frequency domain) Single MIs Output subtraction -2dB nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Conclusions Detecting faint stochastic noises is important in fundamental physics quests, Correlation techniques are used to boost to experimentally test Planck scale effects the sensitivity of the single device of orders of magnitude. At the moment with only (gravitational wave background, quantum classical light. gravity fluctuations…) Quantum light is currently used in single interferometers to boost their sensitivity Single mode Squeezed light and TWB below the SNL provide an enhancement in the sensitivity of coupled interferometers Combining cross-correlation techniques We have realized a table top experiment and quantum enhancement we have mimicking the design of large scale devices demonstrated 1-2 order of magnitude demonstrating quantum advantage, in two sensitivity improvement with respect to the possible configurations single interferometer nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Conclusions Detecting faint stochastic noises is important in fundamental physics quests, Correlation techniques are used to boost to experimentally test Planck scale effects the sensitivity of the single device of orders of magnitude. At the moment with only (gravitational wave background, quantum classical light. gravity fluctuations…) Quantum light is currently used in single interferometers to boost their sensitivity Single mode Squeezed light and TWB below the SNL provide an enhancement in the sensitivity of coupled interferometers Combining cross-correlation techniques We have realized a table top experiment and quantum enhancement we have mimicking the design of large scale devices demonstrated 1-2 order of magnitude demonstrating quantum advantage, in two sensitivity improvement with respect to the possible configurations single interferometer nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
Conclusions Detecting faint stochastic noises is important in fundamental physics quests, Correlation techniques are used to boost to experimentally test Planck scale effects the sensitivity of the single device of orders of magnitude. At the moment (gravitational wave background, with only classical light. quantum gravity fluctuations…) Quantum light is currently used in single interferometers to boost their sensitivity Single mode Squeezed light and TWB below the SNL provide an enhancement in the sensitivity of coupled interferometers Combining cross-correlation techniques We have realized a table top experiment and quantum enhancement we have mimicking the design of large scale demonstrated 1-2 order of magnitude devices demonstrating quantum sensitivity improvement with respect to advantage, in two possible configurations the single interferometer nome, date e luogo della conferenza The Time Machine Factory 2019 – Torino – September 22-25
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