Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity.Though this is abeautiful idea, which may resolve many long standing problems in the theories of gravity, it also raises many otherprob...Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity.Though this is abeautiful idea, which may resolve many long standing problems in the theories of gravity, it also raises many otherproblems.In this article I will comment on some of the problems of Verlinde’s proposal with special emphasis on thethermodynamical origin of the principle of relativity.It is found that there is a large group of hidden symmetries ofthermodynamics, which contains the Poincare group of the spacetime for which space is emergent.This explains thethermodynamic origin of the principle of relativity.展开更多
In this paper we theoretically report an unconventional quantum phase transition of a simple Lipkin- Meshkow-Glick model： an interacting collective spin system without external magnetic field. It is shown that this m...In this paper we theoretically report an unconventional quantum phase transition of a simple Lipkin- Meshkow-Glick model： an interacting collective spin system without external magnetic field. It is shown that this model with integer-spin can exhibit a flrst-order quantum phase transition between different disordered phases, and more intriguingly, possesses a hidden supersymmetry at the critical point. However, for half-integer spin we predict another flrst-order quantum phase transition between two different long-range-ordered phases with a vanishing energy gap, which is induced by the destructive topological quantum interference between the intanton and anti-instanton tunneling paths and accompanies spontaneously breaking of supersymmetry at the same critical point. We also show that, when the total spin-value varies from half-integer to integer this model can exhibit an abrupt variation of Berry phase from π to zero.展开更多
As well known, all higher dimensional Kerr-NUT-Ads metrics with arbitrary rotation and NUT parameters in an asymptotically Ad S spacetime have a new hidden symmetry. In this paper, we show that in the near horizon,the...As well known, all higher dimensional Kerr-NUT-Ads metrics with arbitrary rotation and NUT parameters in an asymptotically Ad S spacetime have a new hidden symmetry. In this paper, we show that in the near horizon,the isometry group is enhanced to include the dilatation and special conformal transformation, and find the conformal transformation contains the cosmological constant. It is demonstrated that for near horizon extremal Kerr-NUT-Ads(NHEK-N-Ad S) only one rank-2 Killing tensor decomposes into a quadratic combination of the Killing vectors in terms of conformal group, while the others are functionally independent.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.10875059
文摘Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity.Though this is abeautiful idea, which may resolve many long standing problems in the theories of gravity, it also raises many otherproblems.In this article I will comment on some of the problems of Verlinde’s proposal with special emphasis on thethermodynamical origin of the principle of relativity.It is found that there is a large group of hidden symmetries ofthermodynamics, which contains the Poincare group of the spacetime for which space is emergent.This explains thethermodynamic origin of the principle of relativity.
基金supported by National Natural Science Foundation of China under Grant Nos.10775091 and 10704049
文摘In this paper we theoretically report an unconventional quantum phase transition of a simple Lipkin- Meshkow-Glick model： an interacting collective spin system without external magnetic field. It is shown that this model with integer-spin can exhibit a flrst-order quantum phase transition between different disordered phases, and more intriguingly, possesses a hidden supersymmetry at the critical point. However, for half-integer spin we predict another flrst-order quantum phase transition between two different long-range-ordered phases with a vanishing energy gap, which is induced by the destructive topological quantum interference between the intanton and anti-instanton tunneling paths and accompanies spontaneously breaking of supersymmetry at the same critical point. We also show that, when the total spin-value varies from half-integer to integer this model can exhibit an abrupt variation of Berry phase from π to zero.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11275099 and 11435006
文摘As well known, all higher dimensional Kerr-NUT-Ads metrics with arbitrary rotation and NUT parameters in an asymptotically Ad S spacetime have a new hidden symmetry. In this paper, we show that in the near horizon,the isometry group is enhanced to include the dilatation and special conformal transformation, and find the conformal transformation contains the cosmological constant. It is demonstrated that for near horizon extremal Kerr-NUT-Ads(NHEK-N-Ad S) only one rank-2 Killing tensor decomposes into a quadratic combination of the Killing vectors in terms of conformal group, while the others are functionally independent.
