Abstract for Next Colloquium
September 24, 2018
11:15am in PH1-223
Refreshments in HSCI-224 from 10:45-11:05am
Gina Passante - Department of Physics and Astronomy, CSU Fullerton
Using Research to Improve the Teaching of Quantum Mechanics
Quantum mechanics is a notoriously difficult subject, in part because the physical laws of QM contradict what we see in the classical world, which can make it challenging for students to develop a quantum intuition. My research focuses on investigating what specific ideas or concepts are most difficult for students, to what extent the instruc-tional paradigm affects student learning, and how can we use this information to improve instruction. In this talk I will discuss current work to investigate student understanding of quantum concepts in multiple different contexts, and how that affects the instructional choices we make.
Fig. above: The fictional quantum mouse was created as a discrete, two-state quantum system that allows us to discuss the postulates of quantum mechanics in a context beyond the spin-1/2 particles. This figure depicts the inner product of the 'tiny-eyed mouse' state (an eigenstate of the 'eye size' operator) with itself.
The Colloquium is a unique opportunity for students to learn about new developments in physics and what physicists do after they graduate. Hosted by the Department of Physics and Astronomy at California State University Long Beach, the weekly meetings invite guests from universities, research laboratories, and industry to present and discuss current topics in physics. All students are encouraged to attend for a well-rounded experience and training in physics.
The following schedule is for Fall 2018. More will be added as the semester progresses.
10-01: Stephan Haas, USC - Plasmonic Superconductivity in Layered Materials
Due to a lack of screening in two dimensions the Coulomb interactions are generally enhanced and consequently play a major role in many-body effects within layered materials. In the theory of superconductivity Coulomb interactions usually enter via an approximate, static, and adjustable parameter µ* which describes effectively the Coulomb repulsion. Here, we overcome this inadequate approach and introduce an ab initio based material-realistic Coulomb description for 2D systems which captures simultaneously material-intrinsic, substrate, and dynamical screening processes. We show that by changing the doping level or the dielectric environment it is possible to tune the electron-plasmon interaction. We use superconducting density functional theory to calculate the superconducting critical temperature and show how by tuning the plasmon dispersion one can control the superconducting state. We observe strong enhancements of the critical temperature (compared to the standard phonon case) for some doping / dielectric combinations, whereas there is a decrease of the critical temperature for other parameter regimes. We discuss the subtle interplay of different factors to explain the calculated results.
10-29: Zhengjun Wang, West Virginia University - Investigations into the nature of magnetism in transition-metal-doped phthalocyanines
Transition-metal-doped phthalocyanines (TMPc, TM = Co, Ni, Cu, V, and Mn, chemical formula: C32H16N8TM) are molecular semiconductors with interesting electrical, optical, and magnetic properties. Consequently, they have been of considerable interest from both fundamental aspects as well as for their potential applications in organic light-emitting diodes (OLED), organic solar cells, nonlinear optical devices, and spintronic devices. In this work, the nature of magnetism in TMPc was investigated by measuring their magnetization and ac magnetic susceptibilities in magnetic fields up to 90 kOe and covering the wide temperature range of 0.5 K to 300 K. These low temperatures and high magnetic field measurements combined with detailed analysis of the data have provided new information about the nature of magnetism of TMPc. Major results include breakdown of the Hund's rules for CoPc, NiPc and MnPc, presence of the linear chain magnetism but without long range magnetic ordering, antiferromagnetic exchange coupling in CoPc and CuPc, ferromagnetic exchange coupling in MnPc, near perfect paramagnetism in VOPc and diamagnetism in NiPc.
We acknowledge with gratitude donations and support from the following present sponsors:
- H.E. and H.B. Miller and Family Endowment
- Benjamin Carter
- The American Physical Society
We also acknowledge with gratitude our past donors: The Forty-Niner Shops, Inc., The Northrop Grumman Foundation, Sandra Dana, Anonymous.
If you wish to support the Colloquium, please contact the colloquium coordinator or the department chair. Thank you!