Question
This state is defined as the sum of the 000 ket and the 111 ket divided by the square root of 2. For 10 points each:
[10h] Name this three-qubit non-biseparable state often cited as an example of a maximally entangled state. Unlike the W state, it can be collapsed to a separable state after the measurement of one of its qubits.
ANSWER: GHZ state [or Greenberger-Horne-Zeilinger state]
[10m] Performing this mathematical operation on a subsystem of GHZ state transforms it into a separable, mixed state. The negative of this operation on a density matrix times its logarithm yields its von Neumann entropy.
ANSWER: trace [accept partial trace]
[10e] Anton Zeilinger, the “Z” in GHZ, received the 2022 Nobel Prize in Physics for observations of the GHZ state and its relation to this theorem about the incompatibility of local hidden variable theories with quantum mechanics.
ANSWER: Bell’s theorem [or Bell’s inequality]
<Science - Physics>
Summary
| 2024 ARGOS @ Brandeis | 03/22/2025 | Y | 2 | 10.00 | 50% | 50% | 0% |
| 2024 ARGOS @ Chicago | 11/23/2024 | Y | 6 | 16.67 | 100% | 67% | 0% |
| 2024 ARGOS @ Christ's College | 12/14/2024 | Y | 2 | 15.00 | 100% | 50% | 0% |
| 2024 ARGOS @ Columbia | 11/23/2024 | Y | 1 | 10.00 | 100% | 0% | 0% |
| 2024 ARGOS @ McMaster | 11/17/2024 | Y | 5 | 18.00 | 100% | 80% | 0% |
| 2024 ARGOS @ Stanford | 02/22/2025 | Y | 3 | 16.67 | 100% | 67% | 0% |
| 2024 ARGOS Online | 03/22/2025 | Y | 2 | 20.00 | 100% | 50% | 50% |
Data
| CLEVELAND, THIS IS FOR YOU! | Thompson et al. | 10 | 10 | 10 | 30 |
| throw away your cards, rally in the streets | I wish it were possible to freeze time so I would never have to watch you retire | 0 | 0 | 10 | 10 |