Packet 8: Bonus 10
This interaction causes triplet spin states to have lower energy than singlet states. For 10 points each:
[10h] Name this interaction caused by the indistinguishability of quantum particles. By the spin-statistics theorem, fermion wavefunctions are antisymmetric under this interaction while boson wavefunctions are symmetric.
ANSWER: exchange interaction
[10m] The exchange interaction couples neighboring spins in the Ising model, which explains this phenomenon. This phenomenon occurs when domains in a solid spontaneously align.
ANSWER: ferromagnetism [prompt on magnetism]
[10e] This scientist names the Hamiltonian describing spins in a lattice and discovered the exchange interaction independently of Paul Dirac. This scientist discovered the uncertainty principle.
ANSWER: Werner Heisenberg [accept Heisenberg Hamiltonian; accept Heisenberg uncertainty principle]
<Editors, Physics> | Packet H
| Editions | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|
| 2 | 132 | 13.18 | 96% | 34% | 2% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| Claremont B | USC A | 0 | 0 | 10 | 10 | E |
| Claremont C | USC B | 0 | 0 | 10 | 10 | E |
| UCLA B | Claremont A | 10 | 10 | 10 | 30 | HME |
| UCLA E | UC Irvine | 0 | 0 | 10 | 10 | E |
| UCLA F | UC Santa Barbara | 0 | 0 | 10 | 10 | E |
| UCSD A | UCLA A | 0 | 0 | 10 | 10 | E |
| UCSD B | UCLA D | 0 | 0 | 10 | 10 | E |
Summary
| Tournament | Edition | Exact Match? | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|---|---|
| UK (North) | UK | Y | 5 | 14.00 | 100% | 40% | 0% |
| UK (South) | UK | Y | 8 | 12.50 | 100% | 25% | 0% |
| Northern California | US | Y | 4 | 20.00 | 100% | 50% | 50% |
| Southern California | US | Y | 7 | 12.86 | 100% | 14% | 14% |
| Eastern Canada (1) | US | Y | 5 | 14.00 | 100% | 40% | 0% |
| Eastern Canada (2) | US | Y | 9 | 14.44 | 100% | 44% | 0% |
| Florida | US | Y | 4 | 12.50 | 100% | 25% | 0% |
| Great Lakes | US | Y | 11 | 15.45 | 91% | 64% | 0% |
| Lower Mid-Atlantic | US | Y | 9 | 14.44 | 89% | 56% | 0% |
| Upper Mid-Atlantic | US | Y | 12 | 15.00 | 100% | 50% | 0% |
| Midwest | US | Y | 9 | 13.33 | 100% | 33% | 0% |
| North | US | Y | 4 | 10.00 | 100% | 0% | 0% |
| Northeast | US | Y | 12 | 10.83 | 92% | 17% | 0% |
| Pacific | US | Y | 8 | 12.50 | 88% | 38% | 0% |
| South Central | US | Y | 7 | 10.00 | 86% | 14% | 0% |
| Southeast | US | Y | 13 | 12.31 | 92% | 31% | 0% |
| Upstate NY | US | Y | 5 | 10.00 | 100% | 0% | 0% |