scholarly journals Probing primordial gravitational waves: Ali CMB Polarization Telescope

2018 ◽  
Vol 6 (1) ◽  
pp. 145-154 ◽  
Author(s):  
Hong Li ◽  
Si-Yu Li ◽  
Yang Liu ◽  
Yong-Ping Li ◽  
Yifu Cai ◽  
...  
Keyword(s):  
Gravitational Waves ◽  
High Energy Physics ◽  
Transition Edge Sensor ◽  
High Energy ◽  
Cpt Symmetry ◽  
Joint Project ◽  
Current Limit ◽  
Scientific Goal ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization

Abstract In this paper, we will give a general introduction to the Ali CMB Polarization Telescope (AliCPT) project, which is a Sino–US joint project led by the Institute of High Energy Physics and involves many different institutes in China. It is the first ground-based Cosmic Microwave Background (CMB) polarization experiment in China and an integral part of China's Gravitational-wave Program. The main scientific goal of the AliCPT project is to probe the primordial gravitational waves (PGWs) originating from the very early Universe. The AliCPT project includes two stages. The first stage, referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet at an altitude of 5250 meters. Once completed, it will be the highest ground-based CMB observatory in the world and will open a new window for probing PGWs in the northern hemisphere. The AliCPT-1 telescope is designed to have about 7000 transition-edge sensor detectors at 95 GHz and 150 GHz. The second stage is to have a more sensitive telescope (AliCPT-2) with more than 20 000 detectors. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio r by one order of magnitude with three years' observation. Besides the PGWs, AliCPT will also enable a precise measurement of the CMB rotation angle and provide a precise test of the CPT symmetry. We show that three years' observation will improve the current limit by two orders of magnitude.

THE POLARIZATION OF THE COSMIC MICROWAVE BACKGROUND DUE TO PRIMORDIAL GRAVITATIONAL WAVES

2006 ◽  
Vol 21 (12) ◽  
pp. 2459-2479 ◽  
Author(s):  
BRIAN G. KEATING ◽  
ALEXANDER G. POLNAREV ◽  
NATHAN J. MILLER ◽  
DEEPAK BASKARAN
Keyword(s):  
Cosmic Microwave Background ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Microwave Background ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization ◽  
Cosmological Inflation ◽  
Gravitational Wave Background ◽  
Review Current ◽  
Rule Out

We review current observational constraints on the polarization of the Cosmic Microwave Background (CMB), with a particular emphasis on detecting the signature of primordial gravitational waves. We present an analytic solution to the Polanarev approximation for CMB polarization produced by primordial gravitational waves. This simplifies the calculation of the curl, or B-mode power spectrum associated with gravitational waves during the epoch of cosmological inflation. We compare our analytic method to existing numerical methods and also make predictions for the sensitivity of upcoming CMB polarization observations to the inflationary gravitational wave background. We show that upcoming experiments should be able either detect the relic gravitational wave background or completely rule out whole classes of inflationary models.

POLARBEAR: Ultra-high Energy Physics with Measurements of CMB Polarization

2008 ◽  
Author(s):  
Adrian T. Lee ◽  
Huan Tran ◽  
Peter Ade ◽  
Kam Arnold ◽  
Julian Borrill ◽  
...  
Keyword(s):  
High Energy Physics ◽  
High Energy ◽  
Ultra High Energy ◽  
Cmb Polarization ◽  
Energy Physics

COSMIC POLARIZATION ROTATION, COSMOLOGICAL MODELS, AND THE DETECTABILITY OF PRIMORDIAL GRAVITATIONAL WAVES

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3493-3500 ◽  
Author(s):  
WEI-TOU NI
Keyword(s):  
Gravitational Waves ◽  
Large Scale ◽  
Lorentz Invariance ◽  
Cosmological Models ◽  
Point Of View ◽  
Fundamental Physics ◽  
Photon Interaction ◽  
Large Scale Magnetic Field ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization

CMB (Cosmic Microwave Background) polarization observations test many aspects of cosmological models. Effective pseudoscalar-photon interaction(s) would induce a rotation of linear polarization of electromagnetic wave propagating with cosmological distance in various cosmological models. CMB polarization observations are superb tests of these models and have the potential to discover new fundamental physics. Pseudoscalar-photon interaction is proportional to the gradient of the pseudoscalar field. From phenomenological point of view, this gradient could be neutrino number asymmetry, other density current, or a constant vector. In these situations, Lorentz invariance or CPT may effectively be violated. In this paper, we review these results and anticipate what more precise observations can tell us about fundamental physics, inflation, etc. Better accuracy in CMB polarization observation is expected from PLANCK mission to be launched this year. Dedicated CMB polarization observers like B-Pol mission, CMBpol mission and LiteBIRD mission would probe this fundamental issue more deeply in the future. With these sensitivities, cosmic polarization rotations from effective pseudoscalar-photon interaction, Faraday polarization rotations from primordial and large-scale magnetic field, and tensor modes effects would have chances to be detected and distinguished. The subtracted tensor-mode effects are likely due to primordial gravitational waves. We discuss the direct detectability of these primordial gravitational waves using space GW detectors.

PRIMORDIAL GRAVITATIONAL WAVES AND INFLATION: POSSIBILITIES FOR DETECTION

2005 ◽  
Vol 20 (33) ◽  
pp. 2503-2519 ◽  
Author(s):  
ASANTHA COORAY
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Large Scale ◽  
Rapid Evolution ◽  
Big Bang ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization ◽  
Density Perturbations ◽  
Merger Rate ◽  
The Big Bang

The curl-modes of Cosmic Microwave Background (CMB) polarization probe horizon-scale primordial gravitational waves related to inflation. A significant source of confusion is expected from a lensing conversion of polarization related to density perturbations to the curl mode, during the propagation of photons through the large scale structure. Either high resolution CMB anisotropy observations or 21 cm fluctuations at redshifts 30 and higher can be used to delens polarization data and to separate gravitational-wave polarization signature from that of cosmic-shear related signal. Separations based on proposed lensing reconstruction techniques for reasonable future experiments allow the possibility to probe inflationary energy scales down to 1015 GeV . Beyond CMB polarization, at frequencies between 0.01 Hz to 1 Hz, space-based laser interferometers can also be used to probe the inflationary gravitational wave background. The confusion here is related to the removal of merging neutron star binaries at cosmological distances. Given the low merger rate and the rapid evolution of the gravitational wave frequency across this band, reliable removal techniques can be constructed. We discuss issues related to joint constraints that can be placed on the inflationary models based on CMB polarization information and space-based interferometers such as the Big Bang Observer.

scholarly journals Detecting Primordial Gravitational Waves: a forecast study on optimizing frequency distribution of next generation ground-based CMB telescope

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Deliang Wu ◽  
Hong Li ◽  
Shulei Ni ◽  
Zheng-Wei Li ◽  
Cong-Zhan Liu
Keyword(s):  
Gravitational Waves ◽  
Focal Plane ◽  
Fixed Number ◽  
Next Generation ◽  
Polarization Experiment ◽  
Frequency Bands ◽  
Atmospheric Window ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization ◽  
Better Than

Abstract Probing primordial gravitational waves is one of the core scientific objectives of the next generation CMB polarization experiment. Integrating more detector modules on the focal plane and performing high accurate observations are the main directions of the next generation CMB polarization telescope, like CMB S4. Also, multi-band observation is required by foreground analysis and reduction, as it is understood that foregrounds have become the main obstacles of CMB polarization measurements. However, ground observation is limited by the atmospheric window and can be usually carried out in one or two bands, like what BICEP or Keck array have done in the south pole. In this paper, we forecast the sensitivity of tensor-to-scalar ratio r that may be achieved by a multi-frequency CMB polarization experiment, basing on which to provide guidance for further expanding frequency bands and optimize the focal plane of a telescope. At the same time, the realization of having two frequency bands in one atmospheric window is discussed. With fixed number of detectors, the simulation results show that, in order to get a good limit, more frequency bands are needed. Better constraints can be obtained when it includes at least three bands, i.e., one CMB channel (95 GHz) + one dust channel (high frequency) and one synchrotron channel (low frequency). For example, 41 + 95 + 220 GHz, which is better than only focusing around the CMB band, like 85 + 105 + 150 GHz, and 95 + 135 + 155 GHz, and this frequency combination is even better than the combination of 41 + 95 + 150 + 220 GHz. As CMB S4 plans to consider two frequency bands in each atmospheric window, and along this way, we find that one CMB band and more bands in synchrotron and dust channels are helpful, for example, 2 bands in lower frequency, 30 + 41 GHz, 2 bands in higher frequency, 220 + 270 GHz, i.e. 30 + 41 + 95 + 220 + 270 GHz, can get better constraints, and in this case, more detectors are asked to be assigned in the CMB channel.

scholarly journals Primordial gravitational waves measurements and anisotropies of CMB polarization rotation

2015 ◽  
Vol 751 ◽  
pp. 579-585 ◽  
Author(s):  
Si-Yu Li ◽  
Jun-Qing Xia ◽  
Mingzhe Li ◽  
Hong Li ◽  
Xinmin Zhang
Keyword(s):  
Gravitational Waves ◽  
Polarization Rotation ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization
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