## Archive for February, 2014

## Pic: Reinhard at the presser

## Interesting pedagogical note of the day

“Scaffolded” learning may be the wrong approach after all.

## Your Daiy Dose of Physics Arrogance :-)

## BBC covers the LBNE (Long Baseline Neutrino Experiment)

## Humor

## Quantum Computing on the Cover of Time Magazine

Quantum computing is featured on the cover of this week’s Time Magazine, the February 17^{th} issue. The story is of particular interest in our department, since Aaron Reinhard and his student coworkers are building an atomic physics experiment that aims to understand the interactions among ultracold, highly excited atoms. These interactions could someday be used to build a scalable quantum computer.

The article in Time focuses on the D-Wave Two, a controversial new commercial product which claims to implement an adiabatic quantum computer which consists of 512 “qubits,” or quantum bits. A quantum computer is a device where the individual bits, or the “ones” and ”zeros“ which encode all the information in the computer, are stored in quantum systems. In a classical computer, each bit can be in either the “zero” state or the “one” state. In a quantum computer, owing to the strange properties of quantum mechanics, each bit can be either in the zero state, the one state, or zero and one *at the same time*. There are several very clever computing algorithms that harness this strange behavior to perform massively parallel operations.

An example of such an process, called Shor’s algorithm, involves the factorization of a large number into its prime factors. Factorization is at the heart of nearly all protocols for data encryption and secure communication. The increase in the speed at which a quantum computer would be able to factor a number compared to a classical computer scales exponentially with the number of bits. This means that numbers which might take years to factor on the best modern classical computers might take seconds to factor using a quantum computer. Numbers that would take the age of the universe to factor on a classical computer, could be factored in months.

The reason the $10 million D-Wave Two is controversial is that it purports to implement adiabatic quantum computation, or a very special kind of quantum computation. Adiabatic quantum computers can only be used for optimization problems, or problems related to finding the fastest or most efficient way to do something. They cannot be used to factor numbers. Gate-type quantum computers are necessary for this task. Adding to the controversy is the fact that several independent tests of the D-Wave Two have not shown any improvement in speed over a classical computer^{1,2}.

Dr. Reinhard’s group is building an experiment where they will trap rubidium atoms and cool them to a few millionths of a degree above absolute zero. They will then excite the atoms’ valence electrons to very high internal states (principal quantum numbers of 40-100) and study the interactions among these neutral atoms. The goal is to understand the properties of the interactions so that they might someday be used to build a gate-based quantum computer made of neutral atoms. The fundamental science involved in the interactions among neutral atoms is of significant interest, but the potential application to the important problem of quantum information is very exciting.

References:

^{1} Boixo et. al. (April 2013). *Quantum annealing with more than one hundred qubits*

^{2} Ronnow et. al. (January 2014). *Defining and detecting quantum speedup*

## Systems Engineering Program Announced

On February 6, Otterbein officially announced a new major in systems engineering, to launch in fall 2015. Systems engineering represents a broad-based engineering education which focuses on the principles of mechanical, industrial, and electrical engineering as well as physics and math. We have received very positive feedback on our curriculum from local industry partners such as Xigent Automation Systems, Worthington Industries, Mettler Toledo, and Emerson Network Power. Therefore, we are confident that our future graduates will be in high demand.

Professors Dave Robertson and Aaron Reinhard of the Physics Department were leaders in the development of this curriculum, and Reinhard was appointed interim director of the program in January 2015. A national search is underway to hire a full-time director, who will start this coming August.

The 3+2 Cooperative Engineering program run by the Physics Department will continue, allowing students the opportunity to pursue areas of engineering other than systems.

For more information, see the Otterbein press release:

http://www.otterbein.edu/Spotlights/otterbein-announces-engineering-major-beginning-fall-2015

or the Systems Engineering website:

http://www.otterbein.edu/public/Academics/Departments/Interdisciplinary/systems-engineering.aspx

or contact either Prof. Reinhard or Prof. Robertson.

## MicroBooNE – Neutrino physics with liquid argon

The neutrino group at Otterbein (that is, myself and one or two students) are busy working on a new experiment called MicroBooNE at the Fermi National Accelerator Lab. This experiment measures the rates of different kinds of neutrino interactions with nuclei by looking at the ionized particle tracks left in a huge tank of liquid argon. An electric field “drifts” the ionization electrons to a set of wires for easy readout.

I’m busy working on several parts of this experiment: namely the event viewer. You can see some simulated data with my Argo Event Viewer. I’m also working on the DAQ (Data AQuisition) group, providing them tools for doing online monitoring of the data. This will allow us to keep an eye on the health of the detector as we set it up and run it.

Philip Kellogg will be working with me next summer trying to identify Michel electrons (electrons resulting from the beta-decay of stopped cosmic-ray muons) and using them to try to measure the energy response of the detector. With a little luck, this will make a great senior thesis. I’ll also be looking for one other lucky student to work on this project.

MicroBooNE is being built now; first data will probably start coming out around the time we start classes after the summer of 2014… but we get to have fun putting the whole thing together very soon.

You can ‘like’ MicroBooNE on their facebook page!

— Nathaniel