Thoughts on entropic gravity in the Parikh-Wilczek tunneling model of Hawking radiation

In this letter, we use the Parikh-Wilczek tunneling model of Hawking radiation to illustrate that a reformulation of Verlinde's entropic gravity is needed to derive the Newton's law for a temperature-varying screen, demanded by the conservation of energy. Furthermore, the entropy stored in the holographic screen is shown to be additive and its temperature dependence can be obtained.Comment: 5 pages, 1 figure, version submitted to EPJ

Quantum Order: a Quantum Entanglement of Many Particles

It is pointed out that quantum states, in general, contain a new kind of orders that cannot be characterized by symmetry. A concept of quantum order is introduced to describe such orders. As two concrete examples, we discussed quantum orders in free fermion systems and in 2D spin-1/2 systems. We generalize the Landau's theory for the classical orders and introduce projective symmetry group and Fermi surface topology to characterize different quantum orders.Comment: 4 pages, 1 figures, RevTeX4, homepage: http://dao.mit.edu/~we

A Linearithmic Time Algorithm for a Shortest Vector Problem in Compute-and-Forward Design

We propose an algorithm with expected complexity of \bigO(n\log n) arithmetic operations to solve a special shortest vector problem arising in computer-and-forward design, where $n$ is the dimension of the channel vector. This algorithm is more efficient than the best known algorithms with proved complexity.Comment: It has been submitted to ISIT 201

An Introduction to Quantum Order, String-net Condensation, and Emergence of Light and Fermions

We review some recent work on new states of matter. Those states cannot be described symmetry breaking and hence contain a new kind of order -- quantum order. Some quantum orders are shown to be closely related to string-net condensations. Those quantum orders lead to an emergence of gauge bosons and fermions from pure bosonic models.Comment: 16 pages. Homepage http://dao.mit.edu/~we