Polarbear is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic in ation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1,274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.

• P.A.R. Ade(School of Physics and Astronomy, Cardiff University)
• Y. Akiba(The Graduate University for Advanced Studies)
• A.E. Anthony(Center for Astrophysics and Space Astronomy, University of Colorado/Department of Astrophysical and Planetary Sciences, University of Colorado)
• K. Arnold(Department of Physics, University of California)
• M. Atlas(Department of Physics, University of California)
• D. Barron(Department of Physics, University of California)
• D. Boettger(Department of Physics, University of California)
• J. Borrill(Computational Cosmology Center, Lawrence Berkeley National Laboratory/Space Sciences Laboratory, University of California)
• S. Chapman(Department of Physics and Atmospheric Science, Dalhousie University)
• Y. Chinone(High Energy Accelerator Research Organization (KEK)/Department of Physics, University of California)
• M. Dobbs(Osaka University)
• T. Elleflot(Department of Physics, University of California)
• J. Errard(Space Sciences Laboratory, University of California/Computational Cosmology Center, Lawrence Berkeley National Laboratory)
• G. Fabbian(AstroParticule et Cosmologie, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu/International School for Advanced Studies (SISSA))
• C. Feng(Department of Physics, University of California)
• D. Flanigan(Department of Physics, University of California/Department of Physics, Columbia University)
• A. Gilbert(Physics Department, McGill University)
• W. Grainger(Rutherford Appleton Laboratory, STFC)
• N.W. Halverson(Center for Astrophysics and Space Astronomy, University of Colorado/Department of Astrophysical and Planetary Sciences, University of Colorado/Department of Physics, University of ColoradoDepartment of Physics, University of Colorado)
• M. Hasegawa(High Energy Accelerator Research Organization (KEK)/The Graduate University for Advanced Studies, Hayama, Miura District)
• K. Hattori(High Energy Accelerator Research Organization (KEK))
• M. Hazumi(High Energy Accelerator Research Organization (KEK)/The Graduate University for Advanced Studies, Hayama, Miura District/Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo)
• W.L. Holzapfel(Department of Physics, University of California)
• Y. Hori(High Energy Accelerator Research Organization (KEK))
• J. Howard(Department of Physics, University of California/Department of Physics, University of Oxford)
• P. Hyland(Physics Department, Austin College)
• Y. Inoue(The Graduate University for Advanced Studies, Hayama, Miura District)
• G.C. Jaehnig(Center for Astrophysics and Space Astronomy, University of Colorado/Department of Physics, University of Colorado)
• A.H. Jaffe(Department of Physics, Imperial College London)
• B. Keating(Department of Physics, University of California)
• Z. Kermish(Department of Physics, Princeton University)
• R. Keskitalo(Computational Cosmology Center, Lawrence Berkeley National Laboratory)
• T. Kisner(Computational Cosmology Center, Lawrence Berkeley National Laboratory/Space Sciences Laboratory, University of California)
• M. LeJeune(AstroParticule et Cosmologie, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu)
• A.T. Lee(Department of Physics, University of California, Berkeley/Physics Division, Lawrence Berkeley National Laboratory)
• E.M. Leitch(Department of Astronomy and Astrophysics, University of Chicago/Kavli Institute for Cosmological Physics, University of Chicago)
• E. Linder(Physics Division, Lawrence Berkeley National Laboratory)
• M. Lungu(Department of Physics, University of California, Berkeley/Department of Physics and Astronomy, University of Pennsylvania)
• F. Matsuda(Department of Physics, University of California)
• T. Matsumura(High Energy Accelerator Research Organization (KEK))
• X. Meng(Department of Physics, University of California)
• N.J. Miller(Observational Cosmology Laboratory)
• H. Morii(High Energy Accelerator Research Organization (KEK))
• S. Moyerman(Department of Physics, University of California)
• M.J. Myers(Department of Physics, University of California)
• M.J. Myers(Department of Physics, University of California, Berkeley)
• M. Navaroli(Department of Physics, University of California)
• H. Nishino(Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo)
• A. Orlando(Department of Physics, University of California)
• H. Paar(Department of Physics, University of California)
• J. Peloton(AstroParticule et Cosmologie, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu)
• D. Poletti(AstroParticule et Cosmologie, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu)
• E. Quealy(Department of Physics, University of California, Berkeley/Physics Department, Napa Valley College, Napa)
• G. Rebeiz(Department of Electrical and Computer Engineering, University of California)
• C.L. Reichardt(Department of Physics, University of California, Berkeley)
• P.L. Richards(Department of Physics, University of California, Berkeley/School of Physics, University of Melbourne, Parkville)
• C. Ross(Department of Physics and Atmospheric Science, Dalhousie University)
• I. Schanning(Department of Physics, University of California)
• D.E. Schenck(Center for Astrophysics and Space Astronomy, University of Colorado/Department of Astrophysical and Planetary Sciences, University of Colorado)
• B.D. Sherwin(Department of Physics, University of California, Berkeley/Miller Institute for Basic Research in Science, University of California)
• A. Shimizu(The Graduate University for Advanced Studies, Hayama, Miura District)
• C. Shimmin(Department of Physics, University of California, Berkeley/Department of Physics and Astronomy, University of California)
• M. Shimon(School of Physics and Astronomy, Tel Aviv University/Department of Physics, University of California, San Diego)
• P. Siritanasak(Department of Physics, University of California)
• G. Smecher(Three-Speed Logic, Inc.)
• H. Spieler(Physics Division, Lawrence Berkeley National Laboratory)
• N. Stebor(Department of Physics, University of California)
• B. Steinbach(Department of Physics, University of California, Berkeley)
• R. Stompor(AstroParticule et Cosmologie, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu)
• A. Suzuki(Department of Physics, University of California, Berkeley)
• S.Takakura(Osaka University/High Energy Accelerator Research Organization (KEK))
• T. Tomaru(High Energy Accelerator Research Organization (KEK))
• B. Wilson(Department of Physics, University of California)
• A. Yadav(Department of Physics, University of California)
• O. Zahn(Physics Division, Lawrence Berkeley National Laboratory)