There are a number of interesting issues that eminate from this article.
It seems that a closed-time-like curve, where an object travels a distance, and returns to where it started(or at least to the period in time just prior), is no different than to state, that to track an object that has transversed in a closed-time-like loop, it remains in the same location?
Surely for a particle to return to it's starting position X it has to transverse across another position away from X,ie Y or Z? If a particle can literally bump into itself at location X, then this particle is responsible for its own motion, it's motion is "self-propelling" via the fact of self-collisions ?
It is interesting that casimir effects are where two distinct and seperate uncharged plates come into a space-time volume, where upon they are "fused" into a one-volume charged object? Could this be produced by particles that are for all intensive purpose's, overlapping across a vicinity of zero time, a closed time loop?
Ok back to reality, or specifically, relative transverse motions. In relativity, the fact remains all of ordinary matter is stuck in the flow of time, contained within the general concept of spacetime.
To remove onself from this flow, and thus transverse across a negative time domain such as the past, one has to literally either re-direct the bulk spacetime (all for one, and one for all! if I go you all come with me?),,thus there would be NO change as there would be no difference in everythings/anything all paths in spacetime, or one has to deviate to such a degree that one detaches from the bulf flow, one has to produce enough baggage as to implement a "time-drag" where one remains static WRT the rest of the bulk matter.
How can one produce some excess baggage so one is left behind within the universe co-moving spacetime bulk?..ok maybe friction is needed? we all experience forms of frictional, cause of braking, slowing down WRT a specific excess speed?..maybe the negative energy density within the casimir plates instigates an actual amplified particle "friction-effect", between two distinct spacetimes?
One energy density is co-moving with the bulk, whilst the other energy density "pulls" local particles away from the flow? (this should be imagined as a gluton like type of liquid)..thus the finite energy is concentrated to "remain" static, against it's natural frequency (brownian motion).
The process of fusion is the bringing together of two distinct objects, be it two colliding branes, two colliding casimir plates, or two ordinary C-D ROM disks, all these processes have resultant excess energies that creates excess particles, some particles drag themselves into a curve, and keep bumping into themselves to such a degree, their friction becomes fusion? ( you do not need heat for fusion process, the Universe emerged from a static cold non thermal brane collision process).
This is a very speculative posting, but it is based on some experiments I undertook some years ago, using two ordinary Compact-Disks, and a little fascinating book on General Relativity.
P.S I totally agree with the Ken Olum, time travel is immpossible within a bulf flowing spacetime!