arXiv subjects

Thomas F. Jordan

Publications and source records attributed to Thomas F. Jordan.

22 records · Page 2Linked to original sources

arXiv2004

Dynamics of initially entangled open quantum systems

Linear maps of matrices describing evolution of density matrices for a quantum system initially entangled with another are identified and found to be not always completely positive. They can even map a positive matrix to a matrix that is not positive, unless we restrict the domain on which the map acts. Nevertheless, their form is similar to that of completely positive maps. Only some minus signs are inserted in the operator-sum representation. Each map is the difference of two completely positive maps. The maps are first obtained as maps of mean values and then as maps of basis matrices. These forms also prove to be useful. An example for two entangled qubits is worked out in detail. Relation to earlier work is discussed.

quant-ph↗

arXiv2004

Modified Newtonian dynamics from acceleration fluctuations

A speculative mathematical model is used to generate the modified Newtonian dynamics called MOND from fluctuations of the number of quanta of quantized acceleration. The one new parameter can be chosen either to make the transition to modification comparable to that obtained from the functions used to fit data with MOND, or to make the modification at larger accelerations comparable in magnitude to the unexplained accelerations of Pioneer 10 and 11.

astro-ph↗

arXiv2003

Steppingstones in Hamiltonian dynamics

Easy steps through essential Hamiltonian dynamics are outlined, from necessary definitions of Poisson brackets and canonical transformations, to a quick proof that Hamiltonian evolution is made by canonical transformations, the quickest proof of Liouville's theorem, and on to Poincare-Cartan integral invariants and completely integrable dynamics, making room, providing tools, and setting the stage for more recent developments.

physics.ed-ph↗

arXiv1995

Weak Decoherence and Quantum Trajectory Graphs

Griffiths' ``quantum trajectories'' formalism is extended to describe weak decoherence. The decoherence conditions are shown to severely limit the complexity of histories composed of fine-grained events.

quant-ph↗