Discovery 2020 Yuta Michimura Department of Physics, University of - - PowerPoint PPT Presentation

Discovery 2020

Yuta Michimura

Department of Physics, University of Tokyo

April 21, 2020 Ando Lab Midterm Seminar

• Looking back on the year 2019
• Working from home
• My plans and expectations for the year 2020
• Hot topics (continued and expanded from 2019)
• Ultralight dark matter search with interferometers
• Optical levitation of photonic crystal mirror
• Lorentz invariance test in space
• SILVIA:

Space Interferometer Laboratory Voyaging towards Innovative Applications

Contents

2

Review: My Plans JFY2019

3 Only upto ~0.97 Mpc Mostly not done Done for some tables KAGRA+ paper not done Work in progress (Paper with Somiya-san published) SILVIA Cavity constructed New collaboration started (PnC, LMA)

Review: My Expectations JFY2019

4 Successful implementation Paper by Enomoto-kun Not achieved Partially done DONE at below 100 Hz Achieved good sensitivity but not started Cryostat constructed PASSED From this year? DONE

Effort Report for 2019

5

• Compared with 2018:
• KAGRA slightly decreased, KAGRA+ halved
• Quantum and dark matter doubled
• DECIGO greatly increased
• Many visits (thank you for supports!)

Effort Report for 2019

6

* Number of days spent was counted for each topic based on my personal record. If n topics on the same day, 1/n was allocated for each topic. For 2018

Effort Report for 2020 (so far)

7

• At first could not concentrate on work
• Now I’m used to it. No commuting is convenient.
• But I started to feel like I’m left behind
• Lucky that most of the work can be done remotely with my

brain and PC (which is not ideal for experimentalists, though)

Working from Home

8

Sleep Sleep Eat Eat Eat Eat Eat Work Work Commute News Shop Chat

• I was expecting a decrease, but slightly increased?

(may be just a coincidence)

Email Traffic over the Month

9

7都府県 緊急事態宣言 https://emailanalytics.com/ Started to work from home Test emails to check granite

• Significant achievements by group members
• New projects such as SILVIA, DANCE and optical levitation

mirror started as anticipated

• Progress in KAGRA much less than anticipated (found

tragedic issues: birefringence and frosting)

• Visited (too?) many places, gave a number of talks,

including lectures at TianQin Research Center and Durham University, and met new people

• Wrote many applications (4 positions, 3 grants, involved in
• ther 6 applications including a big one on dark matter)
• Wrote EPJD review paper on mg-scale optomechanics,

Parity article on KAGRA

• New people related to dark matter
• Time to realize ideas rather than coming up with new ideas?

Summary and News from JFY2019

10

• 2019 was the most productive year by numbers
• But this is just from past activities of group members

Productivity for the Past 10 Years

11

• First big decrease in our group
• 2020 will be the touchstone of our ability to keep up

Number of People in Ando Group

12

• Largest over the past years
• Largest output is expected

Grants for JFY2020

13 Lorentz violation

• observation!

Optical levitation

• mirrors!

Quantum

• mirrors!

Axion

• demonstration!

※間接経費含む

• Work-work balance would be

very important in coming years

• Large scale vs Table top
• Ongoing vs Emerging
• Management vs Implementation

……

Balance between Topics

14

• Remaining things for O4
• OMC, beam shutter
• Optical table cover for TRX and TRY
• upgraded MZM? In-vac RF PDs and RF/DC QPDs?
• Finish KAGRA+ paper, write birefringence paper
• More concrete planning of SILVIA and DECIGO
• Write SILVIA and DECIGO paper
• Absorption calculations for
• ptical levitation mirror
• Start DANCE Act-1 observation
• Introduce polarization optics

to TRX and TRY of KAGRA

• Search for ultralight dark matter

with KAGRA data

My Plans JFY2020

15

• New data analysis on GW polarization
• Better control of filter cavity and more clear squeezing angle

rotation

• Pave the way to optical levitation mirror (photonic crystal or

curvature from coating stress)

• Stability confirmation paper for optical levitation
• Start Lorentz violation search with upgraded setup
• Q measurement at cryogenic temperatures
• Coil-coil actuator paper
• New people in our group

My Expectations JFY2020

16

• June: 16th Patras Workshop @ Trieste, Italy

→ postponed to June 2021

• July: 13th LISA Symposium @ Glasgow, UK ??
• September: 日本物理学会 @ 筑波大学, 熊本大学 ??
• September: 日本天文学会 @ 弘前大学 ??
• September: LVKC @ Cardiff, UK ??
• October: JGRG30 @ 早稲田大学 ??
• March: 日本物理学会 @ 東京大学駒場キャンパス ??

Schedules in JFY2020

17

• 2019 ver (see slides)
• DANCE: Dark matter Axion riNg Cavity Experiment
• Optical levitation of photonic crystal mirror
• Lorentz invariance test in space
• C-DECIGO: km scale GW detector in space
• 2020 ver
• Ultralight dark matter search with interferometers
• Optical levitation of photonic crystal mirror
• Lorentz invariance test in space
• SILVIA: Space Interferometer Laboratory Voyaging

towards Innovative Applications

Hot Topics

18

• Great tool to probe fundamental mysteries of our Universe
• Laser interferometric gravitational wave detectors can be

sensitive to various physics other than gravitational waves

• Small scale experiments can beat large scale experiments

Laser Interferometry

19

Laser

Length change δL/L Gravitational waves Axion Lorentz violation Speed of light change δc/c Fringe change ∝δL/L, δc/c anisotropy

Quantization

• f gravity

Mirror displacement Non-standard forces

Dark matter Dark energy

• We know they exist everywhere and

we know they played an important role in forming our Universe, but we don’t know what they are at all

Dark Matter

21

• Wide range of candidates, but many focused on WIMPs
• WIMP searches will be soon limited by neutrino background

Past Searches: WIMPs

22

PBHs (upto 100 Msun = 1e59 GeV)

A New Era

23

• G. Bertone, T. M. P. Tait, Nature 562, 51 (2018)

• Strong tool to search for ultralight dark matter (wave-like

dark matter)

• Dark matter Axion search with riNg Cavity Experiment

(DANCE)

• I. Obata, T. Fujita, YM, PRL 121, 161301 (2018)
• DM Axion search with laser interferometric GWD
• K. Nagano, T. Fujita, YM, I. Obata, PRL 123, 111301 (2019)
• B-L gauge boson search
• P. W. Graham+, PRD 93, 075029 (2016)
• A. Pierce+, PRL 121, 061102 (2018)
• D. Carney+, arXiv:1908.04797
• Search through fine-structure constant change
• H. Grote & Y. V. Stadnik, PRR 1, 033187 (2019)
• New searches with strong magnets
• R. Creswick, F. T. Avignone III, arXiv:2004.01642

Laser Interferometric Search

24

DANCE

25

• Axion-photon coupling ( ) gives different

phase velocity between left-handed and right- handed circular polarizations

• Measure the difference

as resonant frequency difference in an bow-tie cavity

coupling constant axion field axion mass

• L= 1 m, Finesse = 3e3, Pin= 1 W
• Also good for practicing a cavity experiments

DANCE Act-1

26

• L= 1 m, Finesse= 2e5, Pin= 1 W, Tobs= 3 months
• New idea to do coherent search with two cavities
• Table-top experiment is complementary to large-scale

experiments like GW detectors

DANCE Act-2

27

γ-ray from SN1987A CAST

Axion-photon coupling

DANCE Act-2 (two cavities)

X-ray from M87

KAGRA (3 km)

Advanced LIGO (4 km)

DM Axion Search with GWDs

• Different method is required for linear cavities in GW

detectors

• Axion-photon coupling create

modulation in polarization angle of linear polarization

• Sensitive when modulation period and round-trip time of

light in a cavity are the same

• Can be searched

along with GWs

28

left-handed is faster right-handed is faster p-pol

Modulation at frequency

Laser FI p-pol s-pol (Axion signal) p-pol (GW signal)

• Difference between baryon number and lepton number
• B-L is conserved very well and could be a charge of U(1)B-L

symmetry → It is natural to think that some gauge boson is coupled

• Related to baryon asymmetry

through leptogenesis

B-L Gauge Boson

29

Baryon Lepton

• Several groups proposed laser interferometric search with

GW detectors and mg-scale optomechanical experiments

• P. W. Graham+, PRD 93, 075029 (2016)
• A. Pierce+, PRL 121, 061102 (2018)
• D. Carney+, arXiv:1908.04797
• When mirrors have different

B-L ratio (~neutron ratio), different resonant frequency, or mirrors are apart, amplitude or phase of force acting on mirrors are different and DM signal remains

Gauge Boson Search

30

• KAGRA can outperform aLIGO because of the use of

sapphire mirrors

• Table top experiment can also be used

Search with KAGRA and mg Mirror

31

When DM direction is optimal 1 year observation with designed sensitivity for KAGRA and aLIGO Sensitivity in PRL 122, 071101 (2019) is used for 7-mg pendulum

KAGRA PRC

KAGRA DARM

Advanced LIGO EP tests 7-mg pendulum with fixed mirror

• Dark matter search could

bring light to KAGRA

bKAGRA to dKAGRA

32

Sensitive axion search with OFI rejected beam B-L gauge boson search with POP beam Add polarization

• ptics to TRX

and TRY to search for axion with lower sensitivity

JGW-P2011614

Fine-Structure Constant

• Scalar DM may introduce temporal variation in α
• Variation in α can be searched by looking for

mirror thickness change

• BS thickness by MICH or ITM HR surface

position change by DARM

33

• H. Grote & Y. V. Stadnik,

PRR 1, 033187 (2019)

• Axion-photon conversion under magnetic field

(Primakoff effect)

• LSW probability
• Sensitivity proportional to

Light Shining through Wall (LSW)

34

production γ→a reconversion a→γ

power build up magnetic field cavity length

• See change in the transmitted power
• Modulate input laser polarization to modulate the signal
• Sensitivity will be proportional to
• But it is not a null measurement (room for improvement?)

Proposal to Improve the Sensitivity

35

• R. Creswick, F. T. Avignone III, arXiv:2004.01642

FPAS-100 B=10 T, L=100 m, Finesse=1e5, Pin=7.5 W ALPS-IIc B=5 T, L=100 m, Finesse=1.2e5, Pin= 30 W

Optical Levitation

• Nov 2013: Sandwich proposed at a seminar
• Jan 2014: Ordered a prototype fused silica mirror

3 mm dia. t 0.1 mm, RoC= 30 mm, R>99.95 %

• Apr 2014: Delivered (6 out of 7 are broken)
• Oct 2014-Jan 2020: Torsion pendulum experiment
• Feb 2015: B4 report by Aritomi and Enomoto
• Jan 2016: Master thesis by Kuwahara
• Jan 2018: Master thesis by Wada
• Jan 2019: Master thesis by Kawasaki
• Jan 2020: Master thesis by Kita
• Apr 2019: Proposal to use photonic crystal (seminar)
• Oct 2019: Horizontal restoring force confirmation (elog)
• Dec 2019: PCM collaboration initiated (seminar)
• Apr 2020: Ordered thin fused silica substrates
• Let’s fabricate and characterize of mirrors!

Long History

37

Levitation Mirrors We Want

• First goal is to demonstrate the levitation
• For demonstration, heavier mirror with higher

finesse is OK

38 For SQL Prototype For suspended experiment Mass 0.2 mg ~1.6 mg ~ 7 mg Size (mm) φ 0.7 mm t 0.23 mm φ 3 mm t 0.1 mm φ 3 mm t 0.5 mm RoC 30 mm convex 30±10 mm convex (measured: 15.9±0.5 mm) 100 mm concave (previously flat

• nes were used)

Reflectivity 97 % (finesse 100) >99.95 % (measured: >99.5%) 99.99% Comment

Optics Express 25, 13799 (2017)

Only one out of 8 without big cracks Succeeded

• Mirror transmission give mirror mass (and mirror radius)
• Mirror transmission also gives maximum beam radius

allowed from diffraction loss

Mirror Mass vs Reflectivity

39 Calculation by T. Kawasaki, modified by YM

97%, 0.2 mg (for SQL)

If critical couple, no detuning 9.8 m/s2 Mirror power transmission (R=1-T) Intra-cavity power

99.95%, 1.6 mg (for levitation demonstration)

• Raw Si3N4 membrane (Norcada NX5100DS)
• we have one
• Membrane with photonic crystal
• we need to fabricate
• 3 mm dia. mirror we made in 2014
• we have one
• 3 mm dia. thin fused silica substrate
• in stock, ordered
• 1 inch dia. thin fused silica mirror
• available by summer?
• 3 mm dia. thin fused silica mirror
• available by the end of summer?

Mirrors to Characterize in 2020

40

• By beam profiling of reflected beam and by cavity scan

(Nagano method; see JPS2017s talk)

• Inside the small chamber to avoid contamination of mirrors
• See Chiyoda-kun’s talk

Characterization Method

41

• Steady state temperature can be roughly calculated with
• Absorption of <~10 ppm is necessary (sounds reasonable)

Absorption

42

• Fused silica assumed
• Thickness 0.1 mm assumed

for calculating surface area

• Actual temperature increase

will be higher by x~2 if upper cavity is also considered Temperature for disk shape saturates when radius >> thickness since m, Pcirc and A will be proportional to radius2

Surface area Mirror temperature Environment temperature Emissivity(~0.99) Stefan-Boltzmann constant Absorption

• Since beam density is high, two-photon absorption might

also have to be considered

• The effect of temperature increase to
• Radius of curvature change
• Thermal lensing, wave front distortion
• Cavity length change

etc… should be considered with simulations

(fused silica melting point is ~2000 K)

• Absorption measurements also necessary
• Study on photothermal effects recently reported by ANU
• R. Lecamwasam+, arXiv:1912.07789

(if mirror heating increases cavity length, single optical spring can stabilize the cavity length)

More on Absorption

43

Nanosphere is Hot

44

Even though absorption is low, high temperatures (2,000 K) can be reached because of poor heat transfer to the surrounding gas at low pressures.

• J. Millen+, Nature

Lorentz Violation

• Mar 2011: Monolithic MI experiment at Kyoto (seminar)
• Jul 2011: Proposal for ring cavity at seminar
• Jul 2012 to Oct 2013: Observation run
• Jun 2013: CPT’13 conference (seminar)
• Oct 2014: Submission of PhD thesis
• Jan 2018: Master thesis by Sakai and Takeda
• Continuous rotation

and monolithic optics

• Oct 2019: Almost the same

noise floor at stationary and rotation achieved by Takeda-kun

Even Longer History

46

Apparatus Comparison

turntable laser semi- monolithic

• ptics

vacuum enclosure data logger AC power turntable laser non- monolithic

• ptics

vacuum enclosure data logger AC power rotary connector

Old Model

• non-monolithic optics
• alternative rotation

New Model

• monolithic optics
• continuous rotation

PC PC wireless

• Floor noise at rotation stays almost the same with that at

stationary

• Noise peak at rotation frequency

Latest Sensitivity

48

When rotating (old) When rotating (new) Stationary (old) Stationary (new) Polarization? Intensity? Could be solved with fiber fusion splicing

• Good results are obtained and we need to take the last step

toward the observation (may be its better to just start now?)

• Also can be used for practicing cavity control and noise

hunting

• Setup very close to the setup which can be brought into

space (see seminar slides)

Prospects in 2020

49

• 100 m triangular formation flight demonstration satellite
• Applied for JAXA’s Epsilon class mission (公募型小型)
• Some people previously called FF-DECIGO
• Demonstration for space GW detector

SILVIA

51

• 100 m, 100 g, finesse 100, 10 mW, 1e-13 N/rtHz

Sensitivity

52

SILVIA

TOBA

B-DECIGO LISA TianQin B-DECIGO LISA

aLIGO Cosmic Explorer Einstein Telescope KAGRA

Control Scheme

53

Laser

• Initial link acquisition scheme and lock acquisition scheme
• Demonstration of control scheme with table top experiment
• Simulation of orbital motion with drag-free and cavity

controls taken into account

• Development of actuators and local sensors
• Basic ideas are discussed (in Nagano-kun’s thesis or here

and here), but actual demonstration in table-top experiments and time-domain simulations are very important

• No need to care so much about

noise, focus on scheme

• Launch planned in ~2027

Interesting Topics for SILVIA

54

• Ultralight dark matter search
• DANCE Act-1 cavity experiment

(cavity characterization, noise spectrum…)

• Observing run and data analysis pipeline

(similar to continuous wave search; we are taking KAGRA PRCL and MICH data now!)

• Lorentz violation search
• Hunt for noise peaking at rotation frequency

(alignment, scattered light, fiber splicing…)

• Observing run and data analysis pipeline (similar to DM search)
• Optical levitation
• Mirror characterization
• Absorption calculation
• SILVIA
• Simulation on controls
• Demonstration experiment

Job Advertisement

55 * Red ones can be done from home

• 2020 seems to be an important year for future discovery
• Only you can

motivate yourself

Summary

56