  We propose a cosmological model within the framework of Poincar\'e gauge
gravity, in which the cosmological constant, inflaton, and dark matter
candidate occur naturally from the Higgs mechanism. The coset fields that
parameterize the spontaneous breakdown of the Poincar\'e group to the Lorentz
group can be regarded as a Higgs field. Its kinetic term introduces a
cosmological constant into the Lagrangian. Under the cosmologically homogeneous
and isotropic reduction, the Lorentz connection remains a scalar mode and a
pseudo-scalar mode, while the tetrad remains a scale factor. In this scenario,
the scale factor plays the role of the Nambu-Goldstone boson. We construct a
ghost- and tachyon-free parity-conserving Einstein-Hilbert-Yang-Mills type
Lagrangian as a minimum extension of general relativity in Poincar\'e gauge
gravity. We find that in this model the scalar and the pseudo-scalar modes
obtain masses. Numerical analysis shows that the scalar mode triggers
slow-rolling inflation, while the pseudo-scalar mode behaves as a dark matter
candidate.

General Relativity and Quantum Cosmology