Why Everyone Should Care About Physics
In my junior/senior level condensed matter class, I had students write a paper on a topic of their choice related to our class. One of the grading criteria was that they explain the interest of the topic (including applications) to the tax payer who funds this work. Funding of this type of research generates about double as much in economic advances (jobs, American manufacturing, etc.). This huge return is a significantly higher payoff than almost any other investment (consider stocks, bonds, a savings account, real estate)! I include some edited excerpts from my students’ papers below to demonstrate the usefulness of condensed matter research to everyone!
Modern Computing [Trey McNeely]
Today, computers are a central component of our lives, from keeping people in touch with each other, to creating and storing documents, to running calculations that would take a lifetime to carry out by hand. Computers (and the many devices that use them) are one of the biggest success stories of condensed matter physics, as each component has been invented and improved by a lot of physics research. The processor is the key element in a computer; it takes in a stream of information in the form of “bits,” binary ons and offs, and spits out a stream of answering bits. However, without a way to store those bits. Computers would become nothing more than calculators, and we would still be keeping all of our documents in filing cabinets. Of course, we have ways to store bits, and have for decades. Such permanent storage, referred to as a hard drive, is typically the slowest component in a computer, referred to as a bottleneck. A typical computer user spends more time waiting to access permanently stored data than they spend doing anything else on their computer. Whether loading up a word processor, transferring music to a flash drive, or simply trying to boot a computer, the processor and the RAM vastly outclass permanent storage in terms of speed. So, one of today’s biggest computer engineering goals is fast, non-volatile storage. The two most prevalent current forms of storage are hard drives and solid state drives. Both form have a significant amount of ongoing research, but have disadvantages. The computing field is also open for a possible third option (of which there are several ideas under development) that may be less sensitive to typical changes in properties at the nanoscale, or instead take advantage of these differences.
Superconductors [Kyle Krowpman]
All superconductors share a common feature: that below some critical temperature their electrical resistance decreases abruptly to zero. One common demonstration (search YouTube) of superconductivity is the levitation of a magnet over a superconductor. As the magnetic field is pushed out of the inner part of the superconductor, the field from the above magnet causes it to float for as long as the material is cool enough to be in a superconducting state. For example, superconductors can be used to levitate trains to reduce track friction and turbulence or to allow fast, heat-less computing. The main problem in this field is that typical superconducting temperatures are well below room temperature. And, so much energy would be required to cool to the necessary temperatures that the energy savings is lost. Once this high temperature material is created by researchers, many new applications will be possible.
Creating Fuel from Sunlight [Brandon Yost]
In today’s society, finding a reliable fuel source is of extreme importance. Fossil fuels are a very limited resource and we know that they are quickly running out. To compound this problem, the increasing population causes an increased need for these fuels. Also, the fuel we are burning increases the carbon dioxide levels in the atmosphere, which is becoming a driving force of climate change. If we wish to maintain the same lifestyle that we have all grown used to, we must find a new source of energy that is not only reliable, but also good for the planet. It has been estimated by Osterloh, et. al. that the demand for energy may more than double by mid-century. An obvious solution to this problem is the sun. If we can harvest the sun’s light and convert it into energy, we will have the best known renewable resource. Technology currently exists to do just that, however, a lack of funding has made this technology fairly expensive to do properly. With a process called photocatalytic water splitting, we can place a semiconductor into a bath of water. This semiconductor can absorb the sunlight, increasing the total energy of the semiconductor. The water (2 hydrogen atoms and 1 oxygen atom) can use this increased energy to separate the hydrogen and oxygen. This hydrogen that comes from the split water is exactly what can be used as energy.
Quantum Dots
[Patrick Nelson]
Quantum dots have many potential uses. Quantum dots are very promising optical systems, as they emit light at a very precise energy. They could be used as dyes for biological uses. Current dyes are not holding up to current demands. Other uses include taking advantage of their absorption for photon detectors and photovoltaics (which generate a voltage using energy from incident light, as in solar cells). Additionally, their nature as single photon sources gives them potential use as qubits in quantum computing—a computing technique that uses the spin of the electron rather than charge. This could dramatically reduce the energy inefficiency associated with current computing.
Ferroelectrics
[Viviana Nguyen]
When a neutral atom is placed in an electric field, the positively charged nucleus and the negatively charged electrons will separate slightly in opposite directions along the field. The result is called a dipole moment. Most materials do not have a natural dipole moment (without the electric field), but those that do and if the direction can be controlled are called ferroelectrics. These materials are used in capacitors, flash drive memory, for electronic cooling and even for energy scavenging. Imagine using the kinetic motion of your moving shoes to store energy. Ferroelectrics would allow the conversion of your shoes compression into electricity, much like solar cells convert the sun’s light to electricity.
One of the many reasons global climate change is becoming a problem.
Defects (Imperfections on atomic scales)
[Joey Bright]
Crystal defects or deviations from a perfect crystal lattice are of extreme importance in determining the material properties of real materials that the average individual interacts with on a daily basis. The mechanical properties of many materials, such as steel (the backbone of structures such as skyscrapers and bridges) changes with the amount of impurities introduced. Defects also effect other properties of materials, such as their ability to absorb light or conduct electricity. Imagine the effect these impurities have on solar cells designed to convert the sun’s light to electricity or the flow of electricity in a computer transistor. By manipulating impurities, we can create ideal devices for a wide variety of uses.
Thermal Expansion
[Logan Adkins]
When most materials heat up they start to expand. For example, when water is heated from 70° to 180°F, it can double its volume (before turning into a gas)! There are several reasons why you should care about how things thermally expand. Train rails expand, which can cause the rails to warp in such a way that can derail the train if not properly bolted. Concrete and asphalt mixtures also expand with temperature. Typically cheaper mixtures expand more, which also cause them to fail (break up) upon repeating heating and/or cooling. One interesting field of research is a small number of materials that actually shrink when heated). If combined correctly with materials that expand, one can create systems that do not change dimensions with temperature, allowing less potholes, concrete breakage, etc.