FNI 1H Quantum Mechanics 1 Quantum Mechanics I don't like it, and I'm sorry I ever had anything to do with it. -- Erwin Schrodinger talking about Quantum Physics

FNI 1H Quantum Mechanics2 Quantum Mechanics Photoelectric effect Wave particle duality Characteristic energy Quantum numbers Electron spin Electron tunneling Uncertainty principle Quantum entanglement

FNI 1H Quantum Mechanics3 Quantum Numbers There are four numbers that come into the theory of electron clouds as waves called quantum numbers. The first quantum number, n, is the principle energy level. This is the 1 in 1s 2. It can have the values 1, 2, 3, … The second quantum number, l, is the sublevel. The n th principle energy level has n sublevels. We refer to these sublevels by letters: s, p, d, f, g, h, i, j, k, … Sometimes numbers are used too: 0, 1, 2, 3, …(n-1)

FNI 1H Quantum Mechanics4 Quantum Numbers The third quantum number, m l, is the orbital. Every sublevel has one or more orbitals. The s sublevel has 1 orbital, the p sublevel has 3 orbitals, the d sublevel has 5 orbitals, etc. These orbital can be indicated by the number m l = l, l-1, …0, -1, … -l The fourth quantum number, ms, is the spin of the electron. Electrons can be either spin up or spin down. m s can be either +½ or -½

FNI 1H Quantum Mechanics5 Electron Spin In order for two electrons to occupy the same orbital they must have opposite spin. Electrons can either have spin +½ or –½ Spintronics: This is a new type of electronics which is based on the spin of the electrons. It is possible to filter electrons which have different spins using very thin magnetic films.

FNI 1H Quantum Mechanics6 Electron Tunneling The electron has some probability of penetrating a barrier which it does not have enough energy to overcome. For example an electron can pass through a very thin insulating layer resulting in a tunneling current.

FNI 1H Quantum Mechanics7 Quantum Electrodynamics QED Richard Feynman won his Nobel prize for his work in this field. In QED electric fields are better represented quantum mechanically as the exchange of virtual photons with subatomic particles such as protons and electrons.

FNI 1H Quantum Mechanics8 Insert Quantum Mechanics Cartoon Here

FNI 1H Quantum Mechanics9 Quantum Information and Computers Qubits – consist of logical storage that can be 0, 1 or indeterminant between 0 and 1 Writing data: Excite an electron from E 0 to E 1 Reading data: Excite with energy E 2 -E 1 and analyze the photons given off Quantum entanglement Quantum error correction codes The answer occurs as a superposition of all possible answers Quantum algorithms

FNI 1H Quantum Mechanics10 Quantum Information and Computers Data encryption is the basis for electronic transactions. It relies on the factoring of large numbers which is difficult for ordinary computers to accomplish. Quantum computers would be able to compute the factors in seconds. Quantum computers would also be extremely efficient search engines A 40 qubit computer could complete in 100 steps a calculation that would take a classical computer with a trillion bits several years to compute A 100 qubit computer would be more powerful than all the computers in the world linked together Quantum encryption would result in an unbreakable code Quantum computers have been attempted using NMR Shor’s Algorithm for factoring numbers has been demonstrated on 15

FNI 1H Quantum Mechanics11 Quantum Computers DWave Systems

FNI 1H Quantum Mechanics12 Quantum Entanglement This forms the basis for quantum computing. By a suitable choice of operations carried out on one system a second system can be constrained to a particular set of states. If two particles become entangled then information can be transmitted between them. When you read the state of one system you end up erasing the state of the other system. You can not make multiple copies of quantum information.

FNI 1H Quantum Mechanics13 Quantum Mechanics Photoelectric effect Characteristic energy Quantum numbers Wave particle duality Electron spin Electron tunneling Uncertainty principle Quantum entanglement

FNI 1H Quantum Mechanics14 The Uncertainty Principle The more precisely the position is determined the less precisely the momentum is known. Δx Δp ≥ h/2π where x is location and p is momentum. We cannot predict exactly what will happen but only assign probabilities.

FNI 1H Quantum Mechanics