Minimum length uncertainty relations for a dark energy Universe

時間:2017.12.19(二) 19:00 ~ 20:15
地點:理工大學 R902室
講者:Matthew J. Lake
(School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore )

內容簡介:We consider a possible modification of quantum theory due to the influence of dark energy - the mysterious force driving the present day accelerated expansion of the Universe. In particular, we introduce a dark energy-modified version of Heisenberg's Uncertainty Principle, which implies the existence of a minimum length associated with the quantum gravity scale, i.e. the Planck length. We call this the dark energy-modified minimum length uncertainty relation (DE-MLUR) or dark energy uncertainty principle (DE-UP) for short. In addition, the new relation yields a maximum observable length scale, the de Sitter horizon, which is is given by the reciprocal of the square root of the cosmological constant, Lambda, the term in Einstein's field equations that gives rise to the dark energy density. Numerically, this value is comparable to the present day radius of the Universe. Applying the DE-UP to both charged and neutral particles, we obtain estimates of two limiting mass scales, expressed in terms of the fundamental constants {G, c, h, Λ, e}. Evaluated numerically, the charged particle limit corresponds to the order of magnitude value of the electron mass (me), while the neutral particle limit is consistent with current experimental bounds on the mass of the electron neutrino (mνe ). Possible cosmological consequences of the DE-UP are briefly discussed and we note that these lead naturally to a holographic relation between the bulk and the boundary of the Universe, which strongly implies time-variation of the ratio e2/me. Low and high energy regimes in which dark energy effects may dominate canonical quantum behaviour at the present epoch are identified and the possibility of testing the model using lab-based precision quantum measurements is briefly discussed. 

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