Research
"How was the universe born? Is there an ultimate physical theory that can explain everything in the world, including the creation of the universe?"
The Sakurai Laboratory is aiming to addressing these fundamental questions by conducting observational experiments on the cosmic microwave background (CMB) polarization, which is the key to verifying the comic inflation.
Cosmic inflation is a theory of early universe that describes the exponential expansion of the universe 10-38 seconds after its creation. The expansion is the same scale that an amoeba instantly becomes the size of a galaxy. Cosmic inflation is predicted to originate from quantum fluctuations caused by the interaction between the tiny ultra high-energy density space of the early universe and the gravitational field. It is one of the most important research topics in modern physics, so called the quantization of gravity. |  |
However, we has not yet achieved to find the experimental evidence of the inflation, which is physical phenomenon that comes closest to the creation of the universe. The definitive evidence is the discovery of primordial gravitational waves that are predicted to generate during the inflationary period. The exponential expansion of the universe caused space itself to fluctuate, and the fluctuation propagated as waves. This is primordial gravity waves.
The Cosmic Microwave Background Radiation (CMB) is the oldest light in the universe, emitted about 380,000 years after the birth of the universe. The CMB contains information on the "fluctuations" of the early universe. The precise measurement can provide information on the size, age, composition, and evolutionary history of the universe.
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The CMB polarization experiment aims to experimentally verify inflation by detecting a unique pattern, so called "B-modes", imprinted on the "polarized" component of the CMB by atomic gravity waves. Fierce competition is underway around the world for this verification. The observation of the CMB is also an important tool to explore the parameters of astrophysics and particle physics, such as the large-scale structure of the universe, dark matter, dark energy, and neutrinos.
Sakurai Lab is joining in two international experimental projects, the Simons Observatory ground experiment and the LiteBIRD satellite project, to conduct cutting-edge CMB observations. We are also developing cryogenic devices for industrial applications.
Through precise observations of the Cosmic Microwave Background (CMB) polarization, the SO aims to achieve various scientific goals including inflation, neutrinos, and the large-scale structure of the universe.
In the Sakurai Laboratory, we are responsible for the development of a sapphire half-wave plate system using superconducting magnetic bearings, optical windows with anti-reflection structures, and data analysis.
Sakurai Laboratory is in charge of instrumental developments of the LiteBIRD low-frequency telescope (especially polarization modulators), systematic analysis, galactic emission removal methods, and so on.