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#4
by AsThirtyThree - opened

ima try this!

let me know how it goes :)

let me know how it goes :)

sure,first i will test it with that question:
Question:
Consider a three-qubit system. Let the initial state be a generalized W-GHZ mixture:
∣ψ(0)⟩=12∣000⟩+16(∣011⟩+∣101⟩+∣110⟩)+123∣111⟩|\psi(0)\rangle = \frac{1}{2}|000\rangle + \frac{1}{\sqrt{6}}\left(|011\rangle + |101\rangle + |110\rangle\right) + \frac{1}{2\sqrt{3}}|111\rangle
a) Verify whether this state is normalized (is the sum of the squared coefficients equal to 1?).
b) The system evolves under the Hamiltonian $H = \sum_{i<j} J_{ij},\vec{S_i}\cdot\vec{S_j}$; here $J_{12}=J$, $J_{23}=J$, $J_{13}=2J$ (i.e., an asymmetric, non-triangular coupling β€” qubits 1 and 3 interact twice as strongly as the others). To find the state at time $t$, first decompose it into the joint eigenstates of total spin $S^2$ and $S_z$ (such that the Hamiltonian is diagonal in this basis).
c) At time $t$, trace out qubit 1 and calculate the concurrence of the remaining 2-3 qubit pair. Note: this will be a mixed state because qubit 1 is traced out β€” the pure state formula ($2|ad-bc|$) is invalid here, you need to use Wootters' mixed-state concurrence formula (via the eigenvalues of $\rho\tilde{\rho}$).
d) Calculate the tripartite entanglement (three-tangle, $\tau_{ABC}$) of the three qubits at time $t=0$ and show how it is derived from the sum of the squared bipartite concurrences (CKW inequality: $\tau_{ABC} = C_{A(BC)}^2 - C_{AB}^2 - C_{AC}^2$).
e) Now add a "dissipative coupling" (dissipative two-qubit loss) to the system in the form of $L_1 = \sqrt{\gamma}(S_{1+}S_{2-})$ β€” this is not single-qubit dephasing, but a collective loss channel between two qubits. Discuss why the behavior of the three-qubit entanglement (three-tangle) under this type of Lindblad operator must be fundamentally different from the single-qubit dephasing case seen in the previous question (hint: collective loss channels can form a decoherence-free subspace).

TielCoder is built specifically for agentic coding, not for postgrad math and reasoning! :) You will probably find Tiel underperforming stock 35b-a3b on several hard reasoning and knowledge questions, while winning on coding-specific tasks.

TielCoder is built specifically for agentic coding, not for postgrad math and reasoning! :) You will probably find Tiel underperforming stock 35b-a3b on several hard reasoning and knowledge questions, while winning on coding-specific tasks.

The very reason finetunes and the like exist! I'm looking into making a Q4NX if there's nothing hard-blocking from the template somehow, if the back-end even cares about that.

peculiar-ragdoll changed discussion status to closed

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