Tag: partial-trace

7 Positive semidefinite relationship after partial trace 2020-12-15T17:47:26.110

7 What's the 'physical consistency' in the partial trace scenario? 2021-01-23T23:45:06.900

6 Partial trace over a product of matrices - one factor is in tensor product form 2018-12-25T08:15:27.197

6 Bob applies a projector - what happens to eigenvalues of Alice's reduced state? 2020-10-20T02:17:47.967

5 Only assuming the universe evolves according to a positive trace-preserving map, is there a proof that all subsystem evolution must be CPTP? 2018-05-17T00:23:41.620

5 How many Kraus operators are required to characterise a channel with different start and end dimensions? 2018-12-06T18:35:41.847

5 How does $\mathcal E(\rho)=\mathrm{Tr}_{env}[U(\rho\otimes\rho_{env})U^\dagger]$ turn into $P_0\rho P_0+P_1\rho P_1$? 2018-12-17T06:28:36.610

4 Prove that the partial trace is equivalent to measuring and discarding 2019-10-14T03:09:35.843

4 How is the partial trace related to the operator sum representation? 2019-11-25T13:25:14.487

4 Eigenvalues of a quantum state after partial tracing 2020-09-22T19:56:49.073

4 Non-lockability of quantum max-entropy 2020-09-23T16:43:39.673

4 Is the trace distance between multipartite states invariant under permutations? 2020-11-26T01:30:53.983

4 Calculating the entropy of a quantum state 2021-01-08T09:25:10.673

4 Partial trace and SWAP in the basis of subsystems 2021-02-10T23:12:16.120

4 Does $\frac{\Pi_A\otimes I_B}{\text{Tr}((\Pi_A\otimes I_B)\rho_{AB})}\rho_{AB}=\rho_{AB}$ hold for a state $\rho_{AB}$ and projector $\Pi_A$? 2021-02-23T07:16:32.580

3 Tensor product properties used to obtain Kraus operator decomposition of a channel 2018-06-01T20:40:29.040

3 What are nontrivial examples of $n$-sharable bipartite states? 2019-06-03T12:12:55.817

3 Simulating Classical Probabilistic Transitions with superoperators 2019-12-09T02:28:14.853

3 Does the trace distance between marginals bound the distance between the overall states? 2020-05-13T22:13:10.513

3 Is the partial trace $\mathrm{Tr}_B(\rho)$ equal to $\sum_k \mathrm{Tr}[(\sigma_k\otimes I)^\dagger \rho]\sigma_k$? 2020-08-07T09:57:17.530

3 Quantum marginal problem - constructing a global state from reduced states 2020-10-21T20:04:12.460

3 How can we upper bound the norm of a partial trace? 2020-11-23T21:08:01.107

3 Fidelity of extensions of states 2020-12-02T17:02:35.220

3 Partial Trace of Werner State 2020-12-20T15:33:20.130

2 How to find the reduced density matrix of a four-qubit system? 2019-08-26T21:45:20.287

2 Given partial states, can one construct the best estimate of the full state? 2020-03-08T14:53:00.467

2 Fidelity With Bell State Calculation 2020-04-13T19:03:16.830

2 Where does the term $|\psi\rangle\langle\psi|$ come from while calculating the expectation value? 2021-01-20T06:20:28.490

1 Prove that the partial trace is a quantum operation, finding its Kraus representation 2020-05-07T10:08:28.527

1 What can be inferred about the closeness of reduced qubit states from the closeness of the bipartite quantum state? 2020-07-13T05:50:02.953

1 Is it possible to partial trace the $\chi$-matrix of $4$ qubits $q_0,q_1,q_2,q_3$ to obtain a description of what happens to $q_1$? 2020-07-29T10:04:16.990

1 Can SWAP operators change trace of a product state? 2020-08-07T11:55:27.213

1 Given $\rho,\sigma$ such that $F(\rho,\sigma)=0$, what can we say about $F(\text{Tr}_A(\rho),\text{Tr}_B(\sigma))$? 2020-08-23T22:26:17.623

1 Trace distance bound after partial trace 2020-10-27T06:27:43.080

1 Trace distance of two classical-quantum state with hashing 2020-11-05T07:45:21.747

1 How do I trace out the second qubit to find the reduced density operator? 2021-01-19T21:09:52.320

1 How can I understand these two equations about the indirect measurement? 2021-01-29T06:48:44.707

1 Is there an easy way to calculate the eigenvalues of the partial transpose of a given matrix? 2021-02-15T07:23:53.690

1 Does $\mathrm{tr}(A \otimes B) = \mathrm{tr} (A) \otimes \mathrm{tr}(B)$ hold for partial trace? 2021-02-20T19:25:08.977

0 Which simple property of partial trace are we using here? 2020-02-20T20:55:47.340

0 Prove that $\operatorname{Tr}_B(O_A M)=O_A\operatorname{Tr}_B(M)$ 2020-04-24T20:40:25.863

0 Implementing Partial Trace in IBMs quantum computer 2020-09-17T06:39:13.777

0 What is the conjugate transpose of $|0\rangle_{A}|1\rangle_{B}$? 2021-02-26T20:17:06.090