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** KOÇ UNIVERSITY PHYSICS SEMINAR**

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Speaker: |
Farhang Loran Isfahan University of Technology |

Title: |
Quanta of Dark Energy |

Date: |
August 8, 2019 |

Time: |
15:30 |

Cookie & Tea: |
SCI 129, 15:15 |

Place: |
SCI 129 |

web: |
https://physics-seminars.ku.edu.tr/ |

**Abstract:
**

While quantum field theory in Minkowski spacetime relies on the notion of one particle states, the existence of such states has been controversial in the context of quantum field theory in curved spacetime. In this talk we provide an argument for existence of novel scalar field theories with a consistent particle interpretation of states in nonstationary spacetimes whose propagating modes are completely localized on hypersurfaces without consulting warp factors or potential wells. Furthermore, we argue that the Weinberg’s approach to particles and interactions in Minkowski spacetime can be understood in terms of the representations of the inhomogeneous Lorentz transformations in the Hilbert space dissociated from the spacetime symmetry. Thus it provides a particle interpretation of states in general nonstationary curved spacetimes straightaway. The scalar creepers and the Weinberg particles add to the cosmological constant and can be considered as a dynamical source for the bare cosmological constant.

**Note:** Professor Farhang Loran’s visit to Koç University has been supported by the Turkish Academy of Sciences (TÜBA).

** ****Short Bio:
**Farhang Loran was born in 1978 in Isfahan, Iran. He received his B.Sc. degree in physics from Isfahan University of Technology (IUT) in 1999. In 2002 he received his Ph.D. in physics from IUT and joined IUT as a faculty member. His areas of interest include quantum mechanics and scattering theory, conformal field theory in two dimensions, field theory in curved background and quantum gravity. He is the author of over 40 research publications.