What would happen to you if you went back in time and killed your grandfather? A model using photons reveals that quantum mechanics can solve the quandary—and even foil quantum cryptography

Recently Ralph and his PhD student Martin Ringbauer led a team that experimentally simulated Deutsch’s model of CTCs( Closed Time like Curve)  for the very first time, testing and confirming many aspects of the two-decades-old theory. Their findings are published in Nature Communications. Much of their simulation revolved around investigating how Deutsch’s model deals with the “grandfather paradox,” a hypothetical scenario in which someone uses a CTC to travel back through time to murder her own grandfather, thus preventing her own later birth. (Scientific American is part of Nature Publishing Group.)

Deutsch’s quantum solution to the grandfather paradox works something like this:

Instead of a human being traversing a CTC to kill her ancestor, imagine that a fundamental particle goes back in time to flip a switch on the particle-generating machine that created it. If the particle flips the switch, the machine emits a particle—the particle—back into the CTC; if the switch isn’t flipped, the machine emits nothing. In this scenario there is no a priori deterministic certainty to the particle’s emission, only a distribution of probabilities. Deutsch’s insight was to postulate self-consistency in the quantum realm, to insist that any particle entering one end of a CTC must emerge at the other end with identical properties. Therefore, a particle emitted by the machine with a probability of one half would enter the CTC and come out the other end to flip the switch with a probability of one half, imbuing itself at birth with a probability of one half of going back to flip the switch. If the particle were a person, she would be born with a one-half probability of killing her grandfather, giving her grandfather a one-half probability of escaping death at her hands—good enough in probabilistic terms to close the causative loop and escape the paradox. Strange though it may be, this solution is in keeping with the known laws of quantum mechanics. 

http://www.scientificamerican.com/article/time-travel-simulation-resolves-grandfather-paradox/

Posted By F. Sheikh

The article in the Christian Science Monitor carries a critical message we humans would do well to remember. Mother nature is far more adaptable than we think. It is a good lesson for people who deny climate change.  When humans improve their behavior, nature rewards and we are all better for it.

Nasik Elahi

Setting rivers free: As dams are torn down, nature is quickly recovering –
CSMonitor.com
http://www.csmonitor.com/Environment/2014/0803/Setting-rivers-free-As-dams-are-torn-down-nature-is-quickly-recovering#.U-ex2XpqJlQ.email

Small Animals Live in a Slow-Motion World

The following article is taken from the latest issue of Scientific American

Time seems to pass more slowly for lighter animals with faster metabolisms

One “dog year” supposedly equals seven human years. But does one year feel like seven years to a dog? Evidence suggests that distinct species do indeed experience passing time on different scales. A recent study in Animal Behavior reveals that body mass and metabolic rate determine how animals of different species perceive time.

Time perception depends on how rapidly an animal’s nervous system processes sensory information. To test this ability, researchers show animals a rapidly flashing light. If the light flashes quickly enough, animals (and humans) perceive it as a solid, unblinking light. The animal’s behavior or its brain activity, as measured by electrodes, reveals the highest frequency at which each species perceives the light as flashing. Animals that can detect the blinking at higher frequencies are perceiving time at a finer resolution. In other words, movements and events will appear to unfold more slowly to them—think slow-motion bullet dodging in an action movie.

For further details,  please click the following hyper-link:

http://www.scientificamerican.com/article/small-animals-live-in-a-slow-motion-world/?&WT.mc_id=SA_EVO_20140714