分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-05-09
摘要： We study the structure of the phase space in Horava-Lifshitz theory. With the constraints derived from the action, the phase space is described by five fields, thus there is a lack of canonical structure. The Poisson brackets of the Hamiltonian density do not form a closed structure, resulting in many new constraints. Taking these new constraints into account, it appears that there is no degree of freedom left, or the phase space is reduced to one with an odd number of fields.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2021-08-13
摘要： Generalized Uncertainty Principle (GUP), which manifests a minimal Planck length in quantum spacetime, is central in various quantum gravity theories and has been widely used to describe the Planck-scale phenomenon. Here, we propose a thought experiment based on GUP – as a quantum version of Galileo's falling bodies experiment – to show that the experimental results cannot be consistently described in quantum mechanics. This paradox arises from the interaction of two quantum systems in an interferometer, a photon and a mirror, with different effective Planck constants. Our thought experiment rules out the widely used GUP, and establishes a Quantum Coupling Principle that two physical systems of different effective Planck constants cannot be consistently coupled in quantum mechanics. Our results point new directions to quantum gravity.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-05-08
摘要： We investigate the measure problem in the framework of inflationary cosmology. The measure of the history space is constructed and applied to inflationmodels. Using this measure, it is shown that the probability for the generalized single-field slow roll inflation to last for N e-folds is suppressed by a factor exp(-3N), and the probability for the generalized n-field slow roll inflation is suppressed by a much larger factor, exp(-3nN). Some non-inflationary models such as the cyclic model do not suffer from this difficulty.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2023-02-17
摘要： The paper proposes a statistical fields theory of quantum reference frame underlying the Perelman's analogies between his formalism of the Ricci flow and the thermodynamics. The theory is based on a $d=4-\epsilon$ quantum non-linear sigma model (NLSM), interpreted as a quantum reference frame system which a to-be-studied quantum system is relative to.The statistic physics and thermodynamics of the quantum frame fields is studied by the density matrix of them obtained by the Gaussian approximation quantization. The induced Ricci flow of the frame fields and the Ricci-DeTurck flow of the frame fields associated with the density matrix is deduced. In this framework, the diffeomorphism anomaly of the theory has deep thermodynamic interpretation. The trace anomaly is related to a Shannon entropy in terms of the density matrix, which monotonically flows and achieves its maximal value at the flow limit,called the Gradient Shrinking Ricci Soliton (GSRS). A relative Shannon entropy w.r.t. the maximal entropy gives a statistical interpretation to Perelman's partition function, which is also monotonic and giving an analogous H-theorem to the statistical frame fields system. We find that a temporal static 3-space of the GSRS spacetime is in a thermal equilibrium state, and Perelman's analogies between his formalism and the thermodynamics of the frame fields in equilibrium can be explicitly given in the framework. As a possible underlying microscopic theory of the gravitational system, the theory is also applied to understand the thermodynamics of the Schwarzschild black hole. The cosmological constant in the effective theory of gravity at cosmic scale is also briefly given.
点击量
待评议
点击量
下载量
评论
