Discovery 2020 Yuta Michimura - Department of Physics, University of Tokyo - 東京大学
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Ando Lab Midterm Seminar April 21, 2020
Discovery 2020
Yuta Michimura
Department of Physics, University of Tokyo
Contents
• 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 2
(c)Philip FONG / AFP
Review: My Plans JFY2019
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
3
started (PnC, LMA)
Review: My Expectations JFY2019
Successful implementation
Paper by Enomoto-kun
Not achieved
Partially done
DONE at below
100 Hz
Achieved good
sensitivity but not
started
DONE
Cryostat
constructed
PASSED
From this year?
4
Effort Report for 2019
5
Effort Report for 2019
• Compared with 2018:
- KAGRA slightly decreased, KAGRA+ halved
- Quantum and dark matter doubled
- DECIGO greatly increased
• Many visits (thank you for supports!)
For 2018
45.0%
19.9%
4.6%
0.0%
4.7%
2.3%
15.6%
8.0%
without Virgo
* 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. 6
Effort Report for 2020 (so far)
7
Working from Home
• 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)
Sleep Sleep
Eat
Eat
Work News
Eat Work Eat
Shop
Commute 8
Chat Eat
Email Traffic over the Month
• I was expecting a decrease, but slightly increased?
(may be just a coincidence)
https://emailanalytics.com/
7都府県
Started to work from home 緊急事態宣言
Test emails
to check
granite
9
Summary and News from JFY2019
• 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
other 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?
10Productivity for the Past 10 Years
• 2019 was the most productive year by numbers
• But this is just from past activities of group members
As of April 2020
PhD Thesis
B4->M1
11Number of People in Ando Group
• First big decrease in our group
• 2020 will be the touchstone of our ability to keep up
12Grants for JFY2020
• Largest over the past years
• Largest output is expected
Lorentz violation
- observation!
Optical levitation
- mirrors!
Quantum
- mirrors!
Axion
- demonstration!
※間接経費含む
13Balance between Topics
• Work-work balance would be
very important in coming years
• Large scale vs Table top
• Ongoing vs Emerging
• Management vs Implementation
……
14My Plans JFY2020 • 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 optical levitation mirror • Start DANCE Act-1 observation • Introduce polarization optics to TRX and TRY of KAGRA • Search for ultralight dark matter with KAGRA data 15
My Expectations JFY2020
• 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
16Schedules in JFY2020
• 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 ??
17Hot Topics
• 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
18Laser Interferometry
• 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
Dark
Alternative
polarization
modes
energy
Gravitational Cosmic expansion,
Length change waves inflation
δL/L Boson cloud
Laser
around BHs Dark
B-L bosons
Speed of light Non-standard matter
Mirror forces
change δc/c
Fringe change displacement
wave function
∝δL/L, δc/c anisotropy polarization
Axion extra
collapse
dependence dimensions
Lorentz violation Quantization
quantization of
spacetime of gravity 19Dark Matter
• 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
21Past Searches: WIMPs
• Wide range of candidates, but many focused on WIMPs
• WIMP searches will be soon limited by neutrino background
Park (2007)
https://cerncourier.com/a/defeating-the-background-
in-the-search-for-dark-matter/
PBHs
(upto 100 Msun = 1e59 GeV) 22A New Era
G. Bertone, T. M. P. Tait, Nature 562, 51 (2018)
23Laser Interferometric Search
• 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
24DANCE
• Axion-photon coupling ( ) gives different
phase velocity between left-handed and right-
handed circular polarizations
axion mass
coupling constant axion field
• Measure the difference
as resonant frequency
difference in an bow-tie
cavity
25DANCE Act-1
• L= 1 m, Finesse = 3e3, Pin= 1 W
• Also good for practicing a cavity experiments
∝ma1/2 ∝ma5/4
scan
∝ma5/4
T >T cavity pole
∝ma0 coh obs
∝ma1/4 ∝ma1/2
scan
∝ma1
26DANCE Act-2
• 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
Axion-photon coupling
CAST
γ-ray from SN1987A
X-ray from M87
DANCE Act-2 Advanced LIGO
(two cavities) (4 km)
KAGRA (3 km)
27DM Axion Search with GWDs
• Different method is required for linear cavities in GW
detectors Modulation at
• Axion-photon coupling create frequency
modulation in polarization p-pol
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 left-handed
p-pol is faster
Laser FI
right-handed
p-pol s-pol is faster
(GW signal) (Axion signal) 28B-L Gauge Boson
• 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
Baryon Lepton
• Related to baryon asymmetry
through leptogenesis
浜口幸一 (2017)
29Gauge Boson Search
• 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
30Search with KAGRA and mg Mirror
• KAGRA can outperform aLIGO because of the use of
sapphire mirrors
• Table top experiment can also be used
KAGRA Advanced
DARM LIGO
When DM direction
is optimal
1 year observation
with designed
EP tests sensitivity for
7-mg pendulum
KAGRA and aLIGO
with fixed mirror
Sensitivity in PRL
122, 071101 (2019)
KAGRA PRC is used for 7-mg
pendulum
31bKAGRA to dKAGRA
• Dark matter search could
bring light to KAGRA Add polarization
optics to TRX
and TRY to
search for axion
with lower
sensitivity
B-L gauge boson search
with POP beam
Sensitive axion search JGW-P2011614
with OFI rejected beam
32Fine-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 H. Grote & Y. V. Stadnik,
PRR 1, 033187 (2019)
33Light Shining through Wall (LSW)
• Axion-photon conversion under magnetic field
(Primakoff effect)
production γ→a reconversion a→γ
• LSW probability cavity length
magnetic field
power build up
• Sensitivity proportional to
34Proposal to Improve the Sensitivity
• 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?)
ALPS-IIc
B=5 T, L=100 m,
Finesse=1.2e5, Pin= 30 W
FPAS-100
B=10 T, L=100 m,
Finesse=1e5, Pin=7.5 W
35
R. Creswick, F. T. Avignone III, arXiv:2004.01642Optical Levitation
Long History
• 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! 37Levitation Mirrors We Want
• First goal is to demonstrate the levitation
• For demonstration, heavier mirror with higher
finesse is OK
For SQL Prototype For suspended
experiment
Mass 0.2 mg ~1.6 mg ~ 7 mg
Size (mm) φ 0.7 mm φ 3 mm φ 3 mm
t 0.23 mm t 0.1 mm t 0.5 mm
RoC 30 mm convex 30±10 mm convex 100 mm concave
(measured: (previously flat
15.9±0.5 mm) ones were used)
Reflectivity 97 % >99.95 % 99.99%
(finesse 100) (measured: >99.5%)
Comment Optics Express 25, Only one out of 8 Succeeded
13799 (2017)
without big cracks 38Mirror Mass vs Reflectivity
• Mirror transmission give mirror mass (and mirror radius)
• Mirror transmission also gives maximum beam radius
allowed from diffraction loss If critical couple, no detuning
97%, 0.2 mg
(for SQL)
9.8 m/s2 Mirror power
transmission
(R=1-T)
Beam radius has
to be smaller than
Intra-cavity power
dotted lines
(2*Taperture < Tcoat/10) Calculation by T. Kawasaki,
99.95%, 1.6 mg modified by YM
(for levitation demonstration) (Mirror thickness 0.1 mm,
Beam radius should be smaller than 0.6 mm fused silica assumed to calculate radius.
Critical coupling)
39Mirrors to Characterize in 2020
• 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?
40Characterization Method
• 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
41Absorption
• Steady state temperature can be roughly calculated with
Absorption Environment temperature
Surface area
Emissivity(~0.99) Stefan-Boltzmann constant Mirror temperature
• Absorption of > thickness
since m, Pcirc and A will be
proportional to radius2 42More on 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)
43Nanosphere is Hot
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
Nanotechnology 9, 425 (2014)
44Lorentz Violation
Even Longer History
• 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
46Apparatus Comparison
AC
power
data
logger vacuum enclosure
semi-
PC monolithic
optics
laser data
vacuum enclosure logger laser
non- wireless turntable AC
monolithic
optics rotary power
PC
connector
turntable
Old Model New Model
- non-monolithic optics - monolithic optics
47
- alternative rotation - continuous rotationLatest Sensitivity
• Floor noise at rotation stays almost the same with that at
stationary
• Noise peak at rotation frequency
Polarization?
Intensity?
When rotating Could be solved
(old) with fiber fusion
splicing
Stationary
(old) When rotating
Stationary (new)
(new)
48Prospects in 2020
• 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)
http://qsfp.physics.ox.ac.uk/
49SILVIA
• 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
51Sensitivity
• 100 m, 100 g, finesse 100, 10 mW, 1e-13 N/rtHz
TOBA
TianQin
SILVIA
LISA
B-DECIGO
KAGRA
Einstein Telescope aLIGO
Cosmic Explorer
52Control
Scheme
GW signal
length
servo
Laser
frequency drag-free
servo servo
53Interesting Topics for SILVIA • 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 54
Job Advertisement
• Ultralight dark matter search
- DANCE Act-1 cavity experiment * Red ones can be
(cavity characterization, noise spectrum…) done from home
- 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 55Summary
• 2020 seems to be an important year for future discovery
• Only you can
motivate yourself
56You can also read
