COSMOS CLUSTER 1 - SUMMER 2019
QUANTUM PHYSICS EXPERIMENTS

INSTRUCTORS:  Shirley Chiang, Richard Scalettar, Gary Slizeski

Shirley Chiang's Contact Information:
Department of Physics, 235 Physics/Geology
tel: 530-402-7113; FAX: 530-752-4717
E-mail: chiang@physics.ucdavis.edu

Goals and Plans for Lab Sessions:

Learn how to do experiments. We will start with basic electronics, which is useful for many different kinds of experiments and is also the foundation of modern technology, such as computers, cell phones, and the Internet. We will do experiments on both DC and AC circuits. We will learn how to measure voltage, current, and resistance with a multimeter and how to measure time-varying signals with an oscilloscope. We will do a couple of experiments to measure interesting phenomena, such as the speed of electromagnetic pulses on a coaxial cable and the energies corresponding to the band gaps of light-emitting diodes (LEDs) of different colors. We will also learn how to use operational amplifiers (op-amps) to build simple amplifer and filter circuits. Then we will program an Arduino microcontroller in C to take input from a keyboard or switches, control output devices (blinking LEDs, sound through buzzers, digital to analog conversion of voltage signals), and to do simple experimental data acquisition with analog to digital converters.

The final project is to build a piece of experimental apparatus, a scanning tunneling microscope (STM). The STM is a device based on quantum mechanical tunneling that allows the measurement of the topography of a surface with atomic resolution. Students will build the STM piezoelectric scanner and mount it onto a stage with the sample and tip holders. A stepping motor controlled by a faster Arduino-compatible microcontroller will be used to adjust the sample to tip spacing to put it within the z-range of the scanner, allowing the measurement of the tunneling current. The STM stage will be mounted onto a pneumatic vibration isolation system. Other students will work on programming the microcontroller to do the following processes: (1) digitizing the current and controlling the z-scanner position with a constant current digital feedback loop; (2) the approach procedure, consisting of stepping the motor until the sample and tip are in tunneling range of the z-scanner; (3) sending out the scanning voltages to control the lateral motion of the tip; (4) sending line data z(x,y) to the Linux PC, which will will be used to do the plot of the STM image.

Schedules

Cluster Schedule
Lab Schedule

Lecture Notes
DC Circuits
Kirchhoff's Laws Notes
DC_Circuit_Summary
AC_Circuits
AC Circuits-- Part 2 -- equivalence between complex impedances and calculus for circuits
AC_Circuit_Summary
Op Amps

Lab Exercises
Simple DC Circuits
Kirchhoff's Laws
AC Circuits
Laser Double Slit Interference
Bandpass Filter
Diodes and Band Gaps of LEDs
Op Amps and Active Filters
Pulses
Arduinos and LEDs
Arduino Lab 2 -- Music, Switches, and Potentiometer
Arduino Lab 3 -- D/A and A/D Converters

Electronics References
See website www.allaboutcircuits.com
There is a section there called Textbook: http://www.allaboutcircuits.com/textbook/
and it has chapter on both DC circuits, http://www.allaboutcircuits.com/textbook/direct-current/
and AC circuits, http://www.allaboutcircuits.com/textbook/alternating-current/

Arduino References
 Once you have a UC Davis userid and passphrase, the following books can be downloaded as PDF files from the UC Davis Library:
Brian Evans' book "Beginning Arduino Programming"
Jack Purdum's book "Beginning C for the Arduino."

Reading on Quantum Mechanics
Quantum Jumps
Quantum Tunneling
Scanning Tunneling Microscope

Web links on building a simple STM
A homebuilt STM with Atomic Resolution --Daniel Berard - very impressive!
Amateur STM -- Jürgen Müller
1st STM with disk scanner piezoelectric element -- John Alexander
Arduino PID Library -- Proportional, Integral, Differential Feedback Control -- Explanation

Guest Lectures on Nanotechnology
Prof. Dong Yu -- Physics, UC Davis -- Nanostructured Solar Cells, Monday, July 15, 2019, 2019
Prof. Kai Liu -- Physics, UC Davis -- Nanostructured Materials and Nanomagnetism, Mon. July 22, 2019

Professor Chiang's group webpage

Professor Shirley Chiang
7/11/2019