publications

2025

1. arXiv

   Constraints on the Polarization Angle Oscillations of the Crab Nebula with the Simons Array and Its Applications to the Search for Axion-Like Particles

   T. Adkins, S. S. Arani, K. Arnold, and 26 more authors

   arXiv preprint, 2025

   Abs arXiv HTML

   We present constraints on the polarization angle oscillations of the Crab Nebula observed at millimeter wavelengths with the Simons Array. We find no evidence of global polarization oscillation signals and establish upper bounds on the oscillation amplitudes and the corresponding constraints on axion-like particle (ALP) coupling constants, extending the ALP parameter space probed by CMB experiments.

2. ApJ

   A Measurement of Atmospheric Circular Polarization with POLARBEAR

   T. Fujino, S. Takakura, S. S. Arani, and 20 more authors

   The Astrophysical Journal, 2025

   Abs DOI arXiv HTML

   At millimeter wavelengths, the atmospheric emission is circularly polarized owing to the Zeeman splitting of molecular oxygen by the Earth’s magnetic field. We report measurements of atmospheric circular polarization using three years of observational data from the POLARBEAR experiment at 150 GHz, employing a continuously rotating half-wave plate to modulate and detect the circular polarization signal.

2024

1. PRD

   Exploration of the Polarization Angle Variability of the Crab Nebula with POLARBEAR and Its Application to the Search for Axion-Like Particles

   S. Adachi, T. Adkins, C. Baccigalupi, and 23 more authors

   Physical Review D, 2024

   Abs DOI arXiv HTML

   We examine the polarization angle variability of the Crab Nebula using POLARBEAR millimeter-wave observations and apply these measurements to search for axion-like particles (ALPs). We measure the median 95% upper bound on the polarization oscillation amplitude and derive competitive constraints on the ALP-photon coupling constant as a function of ALP mass, demonstrating the power of bright astrophysical calibration sources as ALP search targets.

2. arXiv

   Calibration of Detector Time Constant with a Thermal Source for the POLARBEAR-2A CMB Polarization Experiment

   S. Takatori, M. Hasegawa, M. Hazumi, and 22 more authors

   arXiv preprint, 2024

   Abs arXiv HTML

   The POLARBEAR-2A (PB-2A) receiver in the Simons Array requires sub-millisecond calibration of bolometer time constants to avoid biasing the polarization signal. We present a new calibrator system using a thermal source to measure and calibrate the time constants of the PB-2A transition edge sensor bolometers, and demonstrate the performance of this system during CMB observations.

3. JATIS

   Design and Performance of a Gain Calibration System for the POLARBEAR-2a Receiver System at the Simons Array Cosmic Microwave Background Experiment

   D. Kaneko, S. Takatori, M. Hasegawa, and 11 more authors

   Journal of Astronomical Telescopes, Instruments, and Systems, 2024

   Abs DOI HTML

   Intensity-to-polarization leakage caused by calibration errors between detectors can be a significant systematic uncertainty for CMB polarization experiments. We describe the design and performance of a gain calibration system for the POLARBEAR-2a receiver in the Simons Array, using a chopped high-temperature ceramic heater as a blackbody source to calibrate detector gain responsivities before and after science observations.

4. JLTP

   Deployment of POLARBEAR-2b

   M. Russell, K. Sakaguri, L. N. Lowry, and 14 more authors

   Journal of Low Temperature Physics, 2024

   Abs DOI HTML

   POLARBEAR-2b (PB-2b) is the second receiver in the Simons Array, a CMB polarization experiment located in the Atacama Desert at 5.2 km altitude. PB-2b contains approximately 7500 detectors operating in two frequency bands at 90 and 150 GHz with arcminute resolution, and its polarization is modulated by a cryogenic continuously rotating half-wave plate. We report on the installation, initial readout commissioning, and early characterization of PB-2b.

2023

1. arXiv

   Predictive Power of Daily Viscacha and Vicuña Sightings on Simons Array Site Work Results

   P. Siritanasak, I. Birdwell, L. Lowry, and 2 more authors

   arXiv preprint, 2023

   Abs arXiv HTML

   We examine whether the daily number of viscacha and vicuña sightings at the Simons Array site in the Atacama Desert, Chile can predict operational work outcomes. Over 31 observation days, we find no statistically significant correlation between animal sightings and site work results, providing a lighthearted but rigorous statistical analysis of a site tradition.

2. PRD

   Constraints on Axion-Like Polarization Oscillations in the Cosmic Microwave Background with POLARBEAR

   S. Adachi, T. Adkins, K. Arnold, and 28 more authors

   Physical Review D, 2023

   Abs DOI arXiv HTML

   Ultralight axion-like particles (ALPs) can couple to photons and induce a time-oscillating birefringence in the CMB polarization at a frequency equal to the ALP mass. We search for this signal in POLARBEAR data and report no detection, setting upper limits on the ALP-photon coupling constant as a function of ALP mass in a mass range inaccessible to other probes.

2022

1. ApJ

   Improved Upper Limit on Degree-Scale CMB B-Mode Polarization Power from the 670 Square-Degree POLARBEAR Survey

   S. Adachi, T. Adkins, M. A. O. Aguilar Faúndez, and 81 more authors

   The Astrophysical Journal, 2022

   Abs DOI arXiv HTML

   We present an improved measurement of the degree-scale CMB B-mode angular power spectrum from 670 square degrees of POLARBEAR data at 150 GHz. By introducing an angle-correction algorithm the data volume is increased by a factor of 1.8. The measured spectrum is consistent with predictions from the Lambda CDM model with Galactic dust foregrounds, and we report improved upper limits on the tensor-to-scalar ratio.

2020

1. ApJ

   A Measurement of the CMB E-Mode Angular Power Spectrum at Subdegree Scales from 670 Square Degrees of POLARBEAR Data

   S. Adachi, M. A. O. Aguilar Faúndez, K. Arnold, and 83 more authors

   The Astrophysical Journal, 2020

   Abs DOI arXiv HTML

   We report a measurement of the CMB E-mode polarization angular power spectrum at 150 GHz using POLARBEAR data spanning 2014–2016 across 670 square degrees at 32 \muK-arcmin noise. The EE power spectrum is measured across multiple acoustic peaks and is consistent with the standard \LambdaCDM cosmological prediction, with a probability-to-exceed of 0.38.

2. ApJ

   Measurement of the Cosmic Microwave Background Polarization Lensing Power Spectrum from Two Years of POLARBEAR Data

   M. Aguilar Faúndez, K. Arnold, C. Baccigalupi, and 82 more authors

   The Astrophysical Journal, 2020

   Abs DOI arXiv HTML

   We present a measurement of the CMB polarization lensing power spectrum using two years of POLARBEAR observations from 2012 to 2014. We reject the no-lensing hypothesis at a confidence level of 10.9 sigma and report a lensing amplitude of A_L = 1.33^+0.46_-0.43(stat+sys), consistent with the \LambdaCDM expectation of A_L = 1.

3. ApJ

   A Measurement of the Degree-Scale CMB B-Mode Angular Power Spectrum with POLARBEAR

   S. Adachi, M. A. O. Aguilar Faúndez, K. Arnold, and 83 more authors

   The Astrophysical Journal, 2020

   Abs DOI arXiv HTML

   We present a measurement of the CMB B-mode polarization power spectrum at degree scales with POLARBEAR. Observations at 150 GHz from 2014 to 2016 achieved a polarization map noise of 32 \muK-arcmin with sensitivity optimized around multipole \ell ≈90, where inflationary gravitational wave signals are predicted to be strongest. The measured spectrum is consistent with \LambdaCDM lensing and Galactic dust foreground models.

4. PRL

   Internal Delensing of Cosmic Microwave Background Polarization B-Modes with the POLARBEAR Experiment

   S. Adachi, M. A. O. Aguilar Faúndez, Y. Akiba, and 82 more authors

   Physical Review Letters, 2020

   Abs DOI arXiv HTML

   We demonstrate internal delensing of CMB polarization B-modes using only POLARBEAR CMB polarization data at subdegree scales, achieving greater than 5-sigma significance. A 14% reduction in B-mode power variance is achieved through internal delensing, improving to 2% with an iterative maximum a posteriori approach. This work demonstrates the capability of internal delensing for improving constraints on inflationary models.

2019

1. RSI

   The POLARBEAR Fourier Transform Spectrometer Calibrator and Spectroscopic Characterization of the POLARBEAR Instrument

   F. Matsuda, L. Lowry, A. Suzuki, and 25 more authors

   Review of Scientific Instruments, 2019

   Abs DOI arXiv HTML

   We describe a Martin-Puplett interferometer Fourier transform spectrometer (FTS) designed to couple to the Huan Tran Telescope and characterize the spectral response of the POLARBEAR receiver. The PB-FTS achieved signal-to-noise ratio >20 for approximately 69% of focal plane detectors, with a throughput of 15.1 sr cm^2, optimized optical coupling, and continuously modulated polarization.

2. ApJ

   Evidence for the Cross-Correlation between CMB Polarization Lensing from POLARBEAR and Cosmic Shear from Subaru Hyper Suprime-Cam

   T. Namikawa, Y. Chinone, H. Miyatake, and 83 more authors

   The Astrophysical Journal, 2019

   Abs DOI arXiv HTML

   We present the first measurement of the cross-correlation between the CMB lensing potential reconstructed from POLARBEAR polarization data and the cosmic shear field from the Subaru Hyper Suprime-Cam survey over an 11 deg^2 region. We reject the null hypothesis at 3.5σsignificance, demonstrating that CMB polarization lensing and galaxy weak lensing probe the same large-scale structure.

3. JCAP

   The Simons Observatory: Science Goals and Forecasts

   The Simons Observatory Collaboration, P. Ade, J. Aguirre, and 189 more authors

   Journal of Cosmology and Astroparticle Physics, 2019

   Abs DOI arXiv HTML

   The Simons Observatory (SO) is a new CMB experiment being built on Cerro Toco in Chile, due to begin observations in the early 2020s. SO will measure CMB temperature and polarization across six frequency bands using 60,000 cryogenic bolometers in three small and one large telescope, targeting primordial perturbations, neutrino properties, and dark energy through wide and deep surveys.

4. ApJ

   Measurements of Tropospheric Ice Clouds with a Ground-Based CMB Polarization Experiment, POLARBEAR

   S. Takakura, M. A. O. Aguilar-Faúndez, Y. Akiba, and 83 more authors

   The Astrophysical Journal, 2019

   Abs DOI arXiv HTML

   We investigate the effect of tropospheric ice clouds on CMB polarization observations with POLARBEAR. Horizontally polarized temporal increases in low-frequency atmospheric fluctuations are detected and correlated with cloud presence at >24σsignificance using three years of data, providing characterization of cloud contamination relevant to all ground-based CMB experiments.

2018

1. JLTP

   The POLARBEAR-2 and Simons Array Focal Plane Fabrication Status

   B. Westbrook, P. A. R. Ade, M. Aguilar, and 86 more authors

   Journal of Low Temperature Physics, 2018

   Abs DOI arXiv HTML

   We present the fabrication status of the POLARBEAR-2A (PB2-A) focal plane, the first of three telescopes in the Simons Array. Each receiver contains seven lenslet-coupled sinuous antenna TES bolometer arrays with 7588 detectors per receiver across 95 and 150 GHz frequency bands. We describe two candidate array designs and present the characterization results demonstrating strong performance metrics required for CMB polarimetry.

2. SPIE

   Studies of Systematic Uncertainties for Simons Observatory: Detector Array Effects

   K. T. Crowley, S. M. Simon, M. Silva-Feaver, and 36 more authors

   In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 2018

   Abs DOI arXiv HTML

   We investigate instrumental systematic effects for the Simons Observatory associated with the detector array and its interaction with the full SO experimental systems. The observatory will measure CMB temperature and polarization across six frequency bands from 27 to 270 GHz. We examine intensity-to-polarization leakage, bolometer nonlinearity, uncalibrated gain variations, and readout crosstalk.

2017

1. ApJ

   A Measurement of the Cosmic Microwave Background B-Mode Polarization Power Spectrum at Sub-Degree Scales from 2 Years of POLARBEAR Data

   The POLARBEAR Collaboration, P. A. R. Ade, M. Aguilar, and 91 more authors

   The Astrophysical Journal, 2017

   Abs DOI arXiv HTML

   We present improved CMB B-mode polarization power spectrum measurements at 150 GHz combining data from two POLARBEAR observation seasons. By incorporating 2013–2014 data with re-analyzed 2012–2013 observations, we achieve a twofold reduction in band-power uncertainties across angular multipoles 500–2100, constraining the lensing B-mode amplitude to A_\mathrmlens = 1.06 \pm 0.24\mathrm(stat) \pm 0.11\mathrm(sys).

2. JCAP

   Performance of a Continuously Rotating Half-Wave Plate on the POLARBEAR Telescope

   S. Takakura, M. Aguilar, Y. Akiba, and 76 more authors

   Journal of Cosmology and Astroparticle Physics, 2017

   Abs DOI arXiv HTML

   We present performance measurements of a continuously rotating half-wave plate (CRHWP) deployed on the POLARBEAR telescope with a 2.5 m primary mirror. The CRHWP allows single detectors to measure all three Stokes parameters, avoiding systematic errors from detector pair mismatches, and improves sensitivity to large angular scales in CMB polarization measurements.

3. A&A

   Making Maps of Cosmic Microwave Background Polarization for B-Mode Studies: The POLARBEAR Example

   D. Poletti, G. Fabbian, M. Le Jeune, and 76 more authors

   Astronomy & Astrophysics, 2017

   Abs DOI arXiv HTML

   We address filtering methods for CMB time-ordered data and construct a general filtering operator that can unambiguously remove any set of unwanted modes. We show this is mathematically equivalent to simultaneously estimating sky signal and unwanted modes while marginalizing over the latter, and investigate conditions for obtaining unbiased sky signal estimates, with results demonstrated on POLARBEAR data.

2016

1. SPIE

   POLARBEAR-2: An Instrument for CMB Polarization Measurements

   Y. Inoue, P. Ade, Y. Akiba, and 71 more authors

   In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII, 2016

   Abs DOI arXiv HTML

   POLARBEAR-2 (PB-2) is a CMB polarization experiment located in the Atacama highland in Chile at 5200 m altitude. Its science goals include measuring CMB polarization signals from both primordial gravitational waves and weak gravitational lensing. PB-2 features a 365 mm focal plane with 7588 dichroic lenslet-antenna-coupled TES bolometers sensitive to 95 and 150 GHz bands.

2. JLTP

   The Broadband Anti-Reflection Coated Extended Hemispherical Silicon Lenses for POLARBEAR-2 Experiment

   P. Siritanasak, P. Ade, Y. Akiba, and 70 more authors

   Journal of Low Temperature Physics, 2016

   Abs DOI HTML

   We present the design and fabrication of broadband anti-reflection (AR) coated extended hemispherical silicon lenses for the POLARBEAR-2 experiment. Each of the 1897 dual-polarization sinuous antenna-coupled pixels in the PB-2 receiver uses a directly contacting silicon lenslet, requiring broad-band AR coatings across 95–150 GHz. We developed a two-layer epoxy-based AR coating using Stycast 1090 and Stycast 2850FT and characterize its optical performance.

3. JLTP

   Development of Readout Electronics for POLARBEAR-2 Cosmic Microwave Background Experiment

   K. Hattori, Y. Akiba, K. Arnold, and 18 more authors

   Journal of Low Temperature Physics, 2016

   Abs DOI arXiv HTML

   We describe the development of readout electronics for the POLARBEAR-2 CMB polarization experiment, which contains 7588 transition edge sensor bolometers requiring frequency-domain multiplexing with a factor of 40. Extending to 40 bolometers requires increased SQUID electronics bandwidth above 4 MHz. We address how the cryogenic readout design affects crosstalk and TES bolometer responsivity.

4. JLTP

   The POLARBEAR-2 and the Simons Array Experiment

   A. Suzuki, P. Ade, Y. Akiba, and 70 more authors

   Journal of Low Temperature Physics, 2016

   Abs DOI arXiv HTML

   We present an overview of the design and status of POLARBEAR-2 (PB-2) and the Simons Array. PB-2 is a CMB polarimetry experiment aimed at characterizing the arcminute angular scale B-mode signal from weak gravitational lensing and searching for degree-scale B-modes from inflationary gravitational waves. The Simons Array deploys three PB-2 type receivers covering 95, 150, and 220 GHz for foreground control.

2015

1. PRD

   POLARBEAR Constraints on Cosmic Birefringence and Primordial Magnetic Fields

   The POLARBEAR Collaboration, P. A. R. Ade, Y. Akiba, and 61 more authors

   Physical Review D, 2015

   Abs DOI arXiv HTML

   We use four-point correlations of E-mode and B-mode CMB polarization from POLARBEAR to investigate cosmic birefringence signals and constrain primordial magnetic fields. The measured signal is consistent with zero, and we establish tighter limits on primordial magnetic fields than previous space-based studies using this ground-based dataset.

2. ApJ

   Modeling Atmospheric Emission for CMB Ground-Based Observations

   J. Errard, P. A. R. Ade, Y. Akiba, and 59 more authors

   The Astrophysical Journal, 2015

   Abs DOI arXiv HTML

   We develop a physically motivated 3D model of atmospheric total intensity emission in the millimeter and sub-millimeter wavelengths for ground-based CMB observations. We derive analytical estimates of correlations between detector time-ordered data as a function of instrument and survey design, and various atmospheric parameters including wind, relative humidity, temperature, and turbulence.

2014

1. ApJ

   A Measurement of the Cosmic Microwave Background B-Mode Polarization Power Spectrum at Sub-Degree Scales with POLARBEAR

   The POLARBEAR Collaboration, P. A. R. Ade, Y. Akiba, and 64 more authors

   The Astrophysical Journal, 2014

   Abs DOI arXiv HTML

   We report a measurement of the B-mode polarization power spectrum of the CMB with POLARBEAR at 150 GHz. Observations over approximately 25 deg^2 across three independent fields at 500 < \ell < 2100 provide evidence for a non-zero B-mode signal at 2.3σsignificance. The best-fit lensing amplitude is A_\mathrmlens = 1.12 \pm 0.61\mathrm(stat)^+0.04_-0.12\mathrm(sys) \pm 0.07\mathrm(mul).

2. SPIE

   Development and Characterization of the Readout System for POLARBEAR-2

   D. Barron, P. A. R. Ade, Y. Akiba, and 68 more authors

   In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII, 2014

   Abs DOI arXiv HTML

   POLARBEAR-2 is a next-generation CMB polarization receiver with 7588 polarization-sensitive TES bolometers read out with 40\times frequency-domain multiplexing. We describe the development and characterization of its readout system, designed to deploy alongside POLARBEAR-1 as part of the Simons Array on Cerro Toco in the Atacama Desert.

3. PRL

   Measurement of the Cosmic Microwave Background Polarization Lensing Power Spectrum with the POLARBEAR Experiment

   The POLARBEAR Collaboration, P. A. R. Ade, Y. Akiba, and 64 more authors

   Physical Review Letters, 2014

   Abs DOI arXiv HTML

   We present the first direct measurement of the CMB polarization lensing power spectrum with POLARBEAR using four-point correlations of E- and B-mode polarization data across approximately 30 square degrees of sky, providing direct evidence for gravitational lensing of the CMB polarization.

4. PRL

   Evidence for Gravitational Lensing of the Cosmic Microwave Background Polarization from Cross-Correlation with the Cosmic Infrared Background

   The POLARBEAR Collaboration, P. A. R. Ade, Y. Akiba, and 64 more authors

   Physical Review Letters, 2014

   Abs DOI arXiv HTML

   We reconstruct gravitational lensing signals from CMB polarization measurements from POLARBEAR and cross-correlate them with infrared background maps from the Herschel satellite. We detect evidence for gravitational lensing of the CMB polarization at 4.0σstatistical significance.

2013

1. ApOpt

   Epoxy-Based Broadband Anti-Reflection Coating for Millimeter-Wave Optics

   D. Rosen, A. Suzuki, B. Keating, and 6 more authors

   Applied Optics, 2013

   Abs DOI arXiv HTML

   We demonstrate epoxy-based anti-reflection coatings for cryogenic millimeter-wave optics. Using multiple-layer coatings where each layer steps in dielectric constant, we achieve low reflection over broad frequency ranges, suppressing reflection to below 10% with two or three coating layers, with direct applications to CMB experiment optics.

2012

1. SPIE

   The Bolometric Focal Plane Array of the Polarbear CMB Experiment

   K. Arnold, P. A. R. Ade, A. E. Anthony, and 53 more authors

   In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VI, 2012

   Abs DOI arXiv HTML

   The POLARBEAR CMB polarization experiment observes from the Atacama Desert in Chile to characterize B-mode polarization from gravitational lensing and search for inflationary gravitational wave signatures. Its focal plane array consists of 1274 polarization-sensitive antenna-coupled bolometers with associated lithographed band-defining filters, cooled to 250 mK.

2. SPIE

   Multi-Chroic Dual-Polarization Bolometric Detectors for Studies of the Cosmic Microwave Background

   A. Suzuki, K. Arnold, J. Edwards, and 12 more authors

   In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VI, 2012

   Abs DOI arXiv HTML

   We develop multi-chroic antenna-coupled TES detectors for CMB polarimetry that boost mapping speed per focal plane area and improve foreground discrimination. Each pixel uses a silicon lens-coupled dual polarized sinuous antenna capturing signals across a broad frequency band, with on-chip filters separating the signal into multiple frequency ranges for simultaneous multi-frequency CMB observations.

3. SPIE

   The POLARBEAR Experiment

   Z. Kermish, P. Ade, A. Anthony, and 53 more authors

   In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VI, 2012

   Abs DOI arXiv HTML

   The POLARBEAR experiment measures CMB polarization on angular scales from 3.5 arcminutes to several degrees using a focal plane of 1274 antenna-coupled, polarization-sensitive TES bolometers cooled to 250 mK. We describe the instrument design, deployment at the Atacama Desert site in Chile, and early science operations.