April 19, 2011 12:14 am

## Explaining Quantum Physics to Your Dog (Or an English Major)

By Steve Rees, Former Managing Editor

As part of the Natural Science and Mathematics (NS&M) Colloquium series this semester, Union College professor Chad Orzel discussed his new book *How to Teach Physics to Your Dog* and how to relate the basics of quantum mechanics to everyday examples in his presentation *What Every Dog Should Know About Quantum Physics*, given in Schaefer Hall last Wednesday.

Orzel was introduced by Assistant Professor of Physics Josh Grossman, who had gone to Williams College with Orzel. Orzel had also been a teaching assistant in one of Assistant Professor of Mathematics Alex Meadow’s classes at Williams.

Orzel began with an introduction of the history of quantum physics. Max Planck, known as the father of quantum physics, was the first to propose a theory of quantum mechanics with his own law, which precisely described the energy radiated by a black body (black object), per unit time, area, solid angle, and frequency. What is unique about the theory is that the graph generated by the law predicts answers with absolute precision, a property of many quantum physics models.

“Its results are tested to unbelievable precision,” said Orzel.

Also in the world of quantum physics was Niels Bohr’s model of the atom as a solar system-styled structure with a positive center of protons and neutrons with circulating orbits of negatively-charged electrons. Einstein, with his work on quantum photoelectric effect theory, came up with one of the first theories of quantum mechanics.

At this point, Orzel explained the point of his most recent book. In the book, Orzel’s dog Emmy asks questions (humorously imitated by Orzel for the audience) related to her own personal interests, such as chasing rabbits and getting treats, and tries to defend her reasoning with quantum physics. Orzel, through his correction of Emmy’s understanding of quantum physics, explains concepts that the readers can more easily follow, teaching them the basics of the expansive world of quantum theory.

One of the chapters, discussing Erwin Schrödinger’s thought experiment of quantum entanglement (more commonly known as Schrödinger’s Cat), Emmy tries to describe how one treat, behind Orzel’s back in one of his hands, really must exist in both hands, since the outside observer does not know for certain if the treat is one hand or another. Orzel corrected her by saying that this is more of a probability issue, since he knows which hand holds the treat and there is a 50 percent chance that it is in the left hand and 50 percent chance that it is in the right.

But, he then explains that in Schrödinger’s model, a thought experiment basically trying to determine if a cat is alive or dead if in a closed box, the observer has no ability to determine if the cat is alive without opening the box. The Copenhagen Interpretation holds that the cat is neither alive nor dead, but in some superpositional state (or quantum entanglement) of being alive and dead at the same time. Once an observer makes a measurement of the system (or opens the box), the superpositional state crashes down into one of two definite states (one with the cat being alive, and the other with the cat being dead).

In the end, Orzel has two treats, one in each hand, and gives them both to Emmy for being such a good dog.

Orzel used this presentation style to explain the behavior of particles as waves, with increasing mass having smaller wavelengths (so that while everything essentially behaves like a wave, a large mass like a dog or human has such a small wavelength that it is impossible to measure its wavelike properties). He also explained some popular quantum physics experiments, including the double slit experiment, and the electron experiment to explain wavelike patterns of light and electrons, and even atomic fusion in the Sun, where hydrogen atoms fuse into helium atoms.

However, the wide applicability of quantum theory has led to some corrupt uses in today’s world, as a means of making money or appearing to have magical abilities. Ideas of quantum healing and quantum attraction are what Emmy would call “evil squirrels,” ways to misinterpret quantum theories to manipulate the uninformed public.

“Some people are confused or manipulate [the theories],” said Orzel, “but they’re all wrong; in reality, it’s math, it’s systematic.”

Orzel concluded with a discussion of the Many Worlds approach, an alternative explanation of quantum entanglement, where multiple universes exist and are created to explain different definite states. For the Schrödinger model, the cat would be dead in one universe and alive in another, which allows all cases to exist in multiple universes at once.

“I thought it was riveting; it was dogtastic,” said sophomore Galen Hench, who attended the lecture. “Seriously though, I thought it was really interesting, and I learned a lot.”

“It was an interesting take on a complicated subject,” said junior Sam Berry. “It was broken down to simple ideas we can relate to, with a bit of humor tossed in.”

The final NS&M lecture, The Post-BP Spill Assessment by William and Mary College professor Robert Diaz, will be on April 20 in Schaefer 106, at 4:40 p.m.