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Transformation optics that mimics the system outside a Schwarzschild black hole

Chen,Huangyang; Miao, Rong-Xin; Li,MiaoSubjects: Physics >> The Physics of Elementary Particles and Fields

We applied the transformation optics to mimic a black hole of Schwarzschild form. Similar properties of photon sphere were also found numerically for the metamaterial black hole. Several reduced versions of the black hole systems were proposed for easier implementations. |

Metamaterials mimicking dynamic spacetime, D-brane and noncommutativity in string theory

Miao,Rong-Xin; Zheng,Rui; Li,MiaoSubjects: Physics >> The Physics of Elementary Particles and Fields

We propose a scheme to mimic the expanding cosmos in 1 2 dimensions in laboratory. Furthermore, we develop a general procedure to use nonlinear metamaterials to mimic D-brane and noncommutativity in string theory. |

Degrees of freedom of f(T) gravity

Miao, Rong-Xin; Li, Miao; Miao,Yan-GangSubjects: Physics >> The Physics of Elementary Particles and Fields

We investigate the Hamiltonian formulation?of?f(T)?gravity?and find that there are five?degrees?of?freedom. The six first class constraints corresponding to the local Lorentz transformation in Teleparallel?gravity?become second class constraints in?f(T)?gravity, which leads to the appearance?of?three extra?degrees?offreedom?and the violation?of?the local Lorentz invariance in?f(T)?gravity. In general, there are D-1 extra?degrees?of?freedom?for?f(T)?gravity?in D dimensions, and this implies that the extra?degrees?of?freedom?correspond to one massive vector field or one massless vector field with one scalar field. |

Violation of the first law of black hole thermodynamics in f(T) gravity

Miao, Rong-Xin; Li, Miao; Miao,Yan-GangSubjects: Physics >> The Physics of Elementary Particles and Fields

We prove that,?in?general?the?first?law?of?black?hole?thermodynamnics, delta Q = T delta S, is violated?in?f(T) gravity. As a result, it is possible that there exists entropy production, which implies that?the?black?hole?thermodynamics?can be?in?non-equilibrium even?in?the?static spacetime. This feature is very different from that?of?f(R) or that?of?other higher derivative gravity theories. We find that?the?violation?of?first?law?results from?the?lack?of?local Lorentz invariance?in?f(T) gravity. By investigating two examples, we note that f ''(0) should be negative?in?order to avoid?the?naked singularities and superluminal motion?of?light. When f ''(T) is small,?the?entropy?of?black?holes?in?f(T) gravity is approximatively equal to (f'(T))/(4)A |

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