1. Quantum Information Science and Technology (QuIST) Stewart D. Personick (sdp) sdp@ece.drexel.edu

2. Quantum Information Science and Technology (QuIST) This is a seminar course (informal, interactive) Attendance is mandatory 3 absences: no penalty >3 absences: -5 points per excess absence Grading: based on homework and participation No exams

3. Overview Preview The concept of the “quantum state” of a physical system or a collection of physical systems The concept of a quantum computer The implications of the quantum model on communications Examples, in depth

4. Preview Mathematical models of the physical world: Newton’s laws (e.g., F=ma) Maxwell’s equations Quantum theory

5. Preview Mathematical models of the physical world: Newton’s laws (e.g., F=ma) Observations -Newton’s laws can be used to explain and model the behavior of physical systems -Not much is counter intuitive about what is predicted (exception: heavy objects fall no faster than light objects)

6. Preview Mathematical models of the physical world: Maxwell’s equations Observations -Maxwell’s equations can be used to explain and model the behavior of physical systems -Much of what is predicted is, at least initially, not very intuitive… but it is not counter intuitive either

7. Preview Mathematical models of the physical world: Quantum Theory Observations -Quantum theory can be used to explain and model the behavior of physical systems -Much of what is predicted is counter intuitive -Every counter intuitive prediction has been verified by subsequent experiments

8. Preview Mathematical models of the physical world: Quantum Theory Observations -Quantum theory may be more than a way of modeling the physical world… it may be a more accurate representation of reality than the physical objects we currently believe to exist -Quantum theory may be an imperfect representation of a physical world that we don’t yet understand -Our applications of quantum theory and the resulting predictions may, themselves, be naïve and imperfect

9. Preview Mathematical models of the physical world: Quantum Theory Observations “If you think you understand this stuff… then you need to think about it some more”

10. Preview Mathematical models of the physical world: Quantum Theory The Schrodinger wave equation: - i h (d/dt) [phi] = 2 (pi) H [phi]

11. Preview Mathematical models of the physical world: Quantum Computer (concept) Let [phi] be selected (caused) to represent the input data to a desired computation. Let the evolution of [phi] according the the Schrodinger equation, represent a computation we wish to perform. Let the outcome of a selected measurement, performed on the system after it has evolved, represent the output data we desire to compute (I.e., the solution).

12. Preview Mathematical models of the physical world: Quantum bit: QuBit (concept) Let [phi1] and [phi2] represent the eigenstates of a simple 2-state quantum system. Then, one can represent any system state as: a[phi1] + b [phi2] For this simple 2-state system, the particular state: a=1 b=0 could represent one of two binary conditions; while a=0 and b=1 could represent the other

13. Preview Mathematical models of the physical world: Quantum bit: QuBit (concept) We need to create the quantum computer equivalents of logic gates. With the appropriate quantum logic gates we can build a quantum computer that can emulate any classical digital computer that can be built with classical logic gates.