Quantum teleportation is a scientific phenomenon that tests the limits of our modern-day intuition; and yet, it’s a systematic consequence of the profound theory of quantum physics, one that builds upon a collection of subtle concepts that, in their own right, dramatically highlight the boundaries of our human intuition. The notion of a quantum state has the strange implication that a quantum particle can be a superposition of two or more states; a measurement will then result in the particle collapsing into one of these states, with a probability than can be precisely calculated. This TED-Ed video on the physicist Erwin Schrödinger's original thought experiment (by Chad Orzel) helps to visualize the quantum superposition of electrons. Prof. L. Del Debbio of the University of Edinburgh has also drafted an online introduction about quantum states and their superposition.

We described the uncertainty principle as the result of an unpredictable scattering between a photon and an electron, and this abbreviated description alludes to a subtle concept: the likelihood of finding a quantum particle anywhere in space is described by a probability function, where this function is formed by the combination of several wave functions. A helpful overview of the uncertainty principle can be found at the Hyper Physics website of Georgia State University or in this online lecture by Prof. J. Schombert at the University of Oregon. After reading up on quantum states and the uncertainty principle, you might check out two TED-Ed videos which give a very accessible explanation on quantum superposition and entanglement (by Josh Samani) and an overview ofthis Einstein’s so-called “spooky action” entanglement thought experiment (TED-Ed video on quantum entanglement by Chad Orzel). A very informative description of quantum entanglement can also be found in this Science News article. Then, challenge yourself and dig into the description of a sophisticated entanglement experiment in this Physical Review Letter by Shalm et al. Quantum physics describes the location of an electron as a probability density, but doesn’t provide an insight into how the electron moves between these various locations. Keeping this fundamentally fuzzy description of quantum particles in mind, does the description of entanglement as an interaction at-a-distance really seem that unusual?

A more expanded definition of the qubit, or quantum bit of data, is available in this Ars Technica article. Finally, the exact mechanism of quantum teleportation (which requires the transmission of two classical digital bits) can be explored with a little more technical insight in this Science article by A. Cho. For this in more rigorous detail check out this Nature letter by Riebe et al.

Sajan Saini is a former materials scientist and science writer. He directs the educational curriculum for AIM Photonics Academy at MIT and lectures at Princeton University. His writings have appeared in Coda Quarterly, MIT Ask an Engineer, and Harper's Magazine. For more on Sajan, please see: https://www.ted.com/profiles/5373010.

Scott Aaronson is the David J. Bruton Centennial Professor of Computer Science at the University of Texas at Austin. His research interests include quantum computing and theoretical computer science; he also writes a blog: http://www.scottaaronson.com.

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