According to a commentary in Physics Today, a new generation of mathematical physicists is needed to “simplify the statistical physics of complex biological systems by recasting it as the exploration of measurable physical parameters in low-dimensional spaces. … Their solutions will require designing new asymptotic approximation methods and numerical simulations of the inherently stochastic particle… Read More »
We investigate a class of entanglement witnesses where each witness is formulated as a difference of two product observables. These observables are decomposable into positive semidefinite local operators that obey a partial ordering rule defined over all their possible expectation values. We provide a framework to construct these entanglement witnesses along with some examples. We… Read More »
We consider the characteristic time operator T introduced in [E. A. Galapon, Proc. R. Soc. Lond. A, 458:2671 (2002)] which is bounded and self-adjoint. For a semibounded discrete Hamiltonian H with some growth condition, T satisfies the canonical relation [T,H]|ψ⟩=iℏ|ψ⟩ for |ψ⟩ in a dense subspace of the Hilbert space. While T is not covariant,… Read More »
We demonstrate that the quantum corrections to the classical arrival time for a quantum object in a potential free region of space, as computed in Phys. Rev. A 80, 030102(R) (2009), can be eliminated up to a given order of ℏ by choosing an appropriate position-dependent phase for the object’s wave function. This then implies… Read More »
Dr. Joseph Bunao is this year’s most outstanding PhD graduate of the National Institute of Physics and the College of Science of the University of the Philippines at Diliman for his excellent academic performance (1.016/1 average grade in graduate school) and outstanding research work (the lead author of three ISI-journal papers). Check out his papers:… Read More »
Abstract We study the conditions when mixtures of maximally entangled pure states remain entangled. We found that the resulting mixed state remains entangled when the number of entangled pure states to be mixed is less than or equal to the dimension of the pure states. For the latter case of mixing a number of pure… Read More »
How long does it take for a message to be delivered? Everyday experience tells us that in order for a message to arrive quicker, we just need a faster messenger. Considering special relativity and quantum mechanics, however, introduces further complications. If we consider the message to be carried by particles, special relativity imposes a minimum… Read More »
Consider a hot cup of coffee, that indispensable fuel for many a physicist. We know that if we leave it alone for long, that hot, steaming cup of coffee cools down, making it easier to drink but less delectable. To delay this, some of us use special insulating cups, or cover the open top of… Read More »