Visualizing Quantum Physics with Matter Waves

Project Title: Visualizing Quantum Physics with Matter Waves

Project Lead's Name: E. Carlo Samson

Project Lead's Email:

Project Lead's Phone: 513-529-0851

Project Lead's Division: CAS

Primary Department: Physics

List Departments Benefiting or Affected by this proposal: Primarily, it will be students from the Department of Physics. But the introductory physics classes also have non-Physics majors; so students from different colleges and departments (e.g. engineering, biology, kinesiology) will also be affected by the equipment procured for this project.

Estimated Number of Under-Graduate students affected per year (should be number who will actually use solution, not just who is it available to): 600

Estimated Number of Graduate students affected per year (should be number who will actually use solution, not just who is it available to): 3

Describe the problem you are attempting to solve and your approach for solving that problem: "Quantum mechanics, that mysterious, confusing discipline, which none of us really understands but which we know how to use. It works perfectly ... in describing physical reality, but it is a 'counter-intuitive discipline', as social scientists would say." This is a quote from Murray Gell-Mann, a Nobel laureate in Physics. Truly, quantum physics has that "reputation" of being a very difficult subject because it is very abstract and counter-intuitive. Unlike classical/Newtonian mechanics, its effects cannot be readily observed in our day-to-day activities.

For example, one of the principles of quantum physics taught in a typical introductory physics class is that particles in the small scale, such as atoms and electrons, behave like waves (as well as behaving like particles, which already makes it confusing). Students will read (and hear from their instructors) that when one lets a beam of electrons pass through two slits, an interference pattern will be observed in a viewing screen, similar to when light (which is a wave) will produce interference patterns when passing through two slits.

This analogy is widely used in universities and high schools because students are expected to have already seen earlier in the semester a light interference pattern from a hands-on experiment on light.

The experiment on light interference involves an actual light source, two slits, and an observation screen. It can be performed as described in the lecture or in any physics textbook. On the other hand, students will merely see a schematic diagram in their books/during the lecture of the electron two-slit (thought) experiment and will be shown a stock photo of an interference pattern, with a caption that says it is the pattern from the interference of electrons.

Students are expected to accept this as truth in itself, without any hands-on activity to reinforce this quantum concept.

Even with the light interference analogy, it is still difficult to imagine how physically distinct objects, such as electrons, can interfere with each other like waves, and produce a pattern. There will be lingering questions even with that analogy:

  • "Do the electrons collide with each other?" Answer: Not really, since you can get the same result if the electrons go through the slits one at a time.
  • "Do they interfere in a way that they destroy each other and the interference pattern is from smashed or smeared out electrons?" Answer: No, that's now how it is; the electrons remain intact.
  • "So how do the electrons know they have to form an interference pattern?" Answer: They don't know it; they just do because they're behaving like light waves, but not really, because light, as we know it from our daily lives, is really a wave.

With the lack of hands-on experimentation, quantum physics will remain "counter-intuitive", mysterious, abstract, hard-to-imagine, and confusing. Alongside this also comes the lack of enthusiasm in since this is the "hottest" field in the industry these days. Also, students, especially non-physics majors, may get the feeling or the opinion that since quantum physics is so far from what they experience in reality, it will never affect their lives anymore after taking that particular Physics course. Unfortunately, quantum physics will become very important to society, as future technologies will be based on it. With the passage into law of the National Quantum Initiative, the growing presence of quantum physics in our daily lives Is further affirmed by the US government in its embrace of investing heavily in the research and development of technologies based on quantum principles, and its emphasis on the necessity for improving education to better prepare a workforce for a quantum-based economy. With this in mind, it is very important that students at Miami University will develop a solid understanding of quantum physics concepts.

At Miami University, the introductory physics classes PHY 161/162/191/192 (engineering, physics, and life sciences majors). and the contemporary physics classes PHY 281/282 (Physics majors) discuss quantum physics topics but are limited by the lack of hands­ on experiments. Interference of particle/matter waves, for example, are discussed using Flash simulations, or watching YouTube videos or other documentaries, and solving physics problems. This is the same scenario in most universities. There is clearly a lack of hands­ on experiments in the introductory level courses regarding quantum physics.

The lack of a hands-on activity regarding quantum physics, especially on the wave-live properties of atoms and electrons, is not because it cannot be done inside a classroom but merely because it was difficult to come up with a physical setup that can demonstrate this principle (...until now). Even Richard Feynman admitted in his famous 1960's introductory physics lectures that his students shouldn't try the electron interference experiment as described in his lecture notes as it " ... has never been done in just this way. The trouble is that the apparatus would have to be made on an impossibly small scale to show the effects we are interested in."

Fortunately, we no longer need to go to the physical size of electrons to observe quantum effects, such as the wave-like interference of quantum particles. In 1995, scientists have created a new state of matter, called Bose-Einstein condensates or BECs. BECs are the coldest physical objects that can exist in the universe, with temperatures close to absolute zero (~50 nanokelvins). This new state is also unique because it exhibits quantum behavior, even though it is orders-of-magnitude larger than electrons. A typical BEC created in a laboratory is around 100 microns, which is the thickness of human hair. With this physical size, a student who wishes to observe quantum phenomena with a BEC will only need a microscope. But the convenience of observing quantum effects with a BEC comes with a price: since BECs can only exist at a very cold microscope, only very low light levels can be used to illuminate it. And low light levels require a very sensitive camera, which brings us to the primary goal of this project.

PRIMARY GOAL: The primary objective of this project is to develop an imaging/observation setup where quantum effects, such as matter-wave interference, can be directly observed by students using BECs produced in the BEC laboratory of Miami's Physics department. BECs can be created on-demand in this laboratory, and students will be able to perform hands-on experiments that can explore quantum principles that they study in their introductory/modem physics classes. As stated above, BECs are quantum objects but are as large as the width of human hair. Any quantum effects can be easily observed with a "microscope" and captured with a camera.

However, with the required low light level illumination, these experiments will need a high-end charge-coupled device (CCD) camera. Additionally, in order to observe the dynamics of the BEC (in the order of microseconds), the camera must have a high acquisition rate. For example, one activity that Miami students can perform for understanding interference of quantum particles: create two BECs, place them close to each other and allow them to interfere. With the existing custom-built microscope in the BEC laboratory, and with a high-sensitivity, fast-acquisition-rate CCD camera, Miami students can observe how physical distinct quantum objects can form interference patterns. The fast acquisition of the camera will even allow students to create a "time-lapse" movie from a sequence of images of a BEC in order to observe quantum dynamics, e.g. capturing the sequence of two BECs rearranging itself neatly into an interference pattern when they interfere.

How would you describe the innovation and/or the significance of your project: First, research studies in physics education have shown that active engagement of the student during the learning process is essential to achieve what is called "deep learning", and it has been quantitatively shown, through improved test scores and higher grades, that this leads to improved understanding of a physics concept. The Physics department has embraced this teaching philosophy by structuring the introductory physics courses (PHY 161/162/191/192) in a SCALE-UP environment, wherein students have hands-on activities to reinforce the physics concepts. By adding hands-on experiments in quantum physics topics using BECs, Miami University would be one in a handful of universities (and possibly the only one in Ohio, as there are no other BEC laboratories in other Ohio universities) to do this.

Secondly, in instances during the semester wherein the introductory physics and contemporary physics courses are not using the imaging setup for quantum physics experiments, it will be used by Physics undergraduate and graduate students in performing independent studies/senior capstone thesis projects regarding BEC physics research. Again, there is only a handful of universities that involve undergraduates in BEC research, and the capability to observe the dynamics of BECs with the fast acquisition camera will further expand the possible research topics that students using the BEC laboratory can explore. On average, there are 8 undergraduates and 2 Master's students who use the BEC laboratory. In the past, the undergraduate students have presented work done in the BEC lab in the Ohio regional conference of the American Physical Society (OSAPS), wherein one student has won the "Best Undergraduate Poster'' award in the Spring 2018 meeting, and national conferences, such as DAMOP, which is the annual major conference for those in the field of atomic, molecular, and optical physics. This has allowed the undergraduate students to network with other students and other professors in the same field and gave them ideas on which universities they can apply to if they want to pursue graduate studies.

How will you assess the success of the project: For the introductory physics (PHY 191/192/161/162) and contemporary physics (PHY 281/282) classes, a before and after questionnaire will be given as part of their lab activity. In this questionnaire, the students' understanding of interference in the context of quantum particles (electrons, atoms) will be asked based on what they have read from their textbook. After performing the hands-on experiment with BECs and how they interfere, their understanding of the material will again be gauged, and feedback will be obtained whether having a hands-on experiment improved their understanding or visualization of the quantum physics topic, or whether the images that they see in their textbooks have now a better context than without a hands-on experiment.

For the independent study/senior capstone/thesis projects, students will be asked to present posters/oral presentations at regional and national conferences. These conferences typically require an abstract or a short paper to be submitted, which will be peer-reviewed to determine if the research project can be presented. The success rate in the submission process will be used to assess this part of the project.

Financial Information

Total Amount Requested: $42,200

Budget Details: The PIX'S:1024BR Digital CCD Camera System will be purchased from Princeton Instruments. This camera allows for low-light-level illumination. It also has a "kinetics" mode, which allows for fast acquisition rates, from which "time-lapse" videos from several images can be created.

Is this a multi-year request: No

Please address how, if at all, this project aligns with University,  Divisional, Departmental or Center strategic goals: As stated above, it will improve understanding of quantum physics topics in Miami students taking Physics courses. At present, industries are becoming aware that they require a workforce that has knowledge of quantum physics and quantum information/computing. With a better understanding of quantum physics, Miami students will be better prepared for future careers.

Also, with the use in independent research/senior capstone, this work is aligned with the Miami Plan for requiring students to have experiential learning.