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.

Highlights

  • Searching for gravitational waves (GWs) has long been the cornerstone of cosmology and astrophysics since Einstein proposed the General Relativity (GR) in early 20th century

  • Different from the GWs detected by LIGO and Virgo, the PGWs arise from quantum fluctuations and carry important information about the very early Universe, for example, the physics of inflation, bouncing and emergent Universe

  • ALICPT AND ITS SCIENTIFIC GOALS we provide a brief introduction to the main contents and scientific goals of the AliCPT project

Read more

Summary

INTRODUCTION

Searching for gravitational waves (GWs) has long been the cornerstone of cosmology and astrophysics since Einstein proposed the General Relativity (GR) in early 20th century. LIGO and Virgo have announced other three events of black hole [2,3,4] and one event of neutron stars GWs [5] These achievements make the GWs study to enter a new era and were awarded the Nobel Prize in Physics in 2017. Different from the GWs detected by LIGO and Virgo, the PGWs arise from quantum fluctuations and carry important information about the very early Universe, for example, the physics of inflation, bouncing and emergent Universe. The CMB B-mode polarization induced by the tensor fluctuations generated in the early Universe, i.e., the PGWs, still have not been detected conclusively. The CMB B-mode polarization induced by the tensor fluctuations generated in the early Universe, i.e., the PGWs, still have not been detected conclusively1 This has become a key scientific goal of CMB.

OVERVIEW OF THE ALICPT SITE
Sensitivity on r and its implication on the Early Universe Physics
Findings
SUMMARY

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.