Tag Info

Accepted

40th Question IBM Sample test

Qubits are initially in the ∣0⟩ state. The Rz gate, which is a rotation around the z-axis, only changes the phase of the qubit states and not the probabilities of measuring 0 or 1 in the computational ...
• 618

Complexity of translation between Measurement Based and Circuit Based with Error Correction

Accourding to Browne et al. it seems the translation from GBQC to MBQC is of size O(N^3) and from MBQC to GBQC the translation is of size ...

pennylane: How to carry out MB rotation without CB rotation?

Good question - let me give it a shot. First of all, note that the application of a single-qubit gate before a measurement in the computational basis is mathematically the same as doing a projective ...
• 33

pennylane: How to carry out MB rotation without CB rotation?

What an interesting observation 😄 I work on the PennyLane team so hopefully I can help you. While indeed, the demo does use RZ in the MBQC part, it is not a gate that mandatorily needs to be added in ...
Accepted

Equivalence of circuits in measurement-based QC

In step 2, you are doing two measurements, $X$ on qubit 1 and $X$ on qubit 2. To move to step 3, you need to bring these measurements earlier in the circuit, which means updating what they look like ...
• 60.5k

Equivalence of circuits in measurement-based QC

If $AU \equiv UB$ then $M_{A} \cdot U \equiv U \cdot M_B$. Measuring $B$ before $U$ is equivalent to measuring $A$ after $U$ if $U$ conjugates $B$ into $A$. The transition from step 2 to step 3 is ...
• 40.6k

Complexity of translation between Measurement Based and Circuit Based with Error Correction

Stabilizer simulation can be done in $O(gq + rq^2)$ time, where $g$ is the total number of operations, $q$ is the number of qubits, and $r$ is the number of measurements that needed random results. ...
• 40.6k
Accepted

Fault tolerance of MBQC

In "Fault-tolerant quantum computation with cluster states"[1], Nielsen and Dawson (2005) studied fault-tolerance in MBQC with cluster states. They proved threshold theorems similar to the ...
• 11.5k

How does measurement based quantum computing (MBQC) behave under error propagation?

Because of the deferred measurement principle, any circuit where measurement amplified errors could be translated into a circuit where unitary operations amplified errors. Therefore measurements can't ...
• 40.6k
Accepted

• 60.5k
1 vote

Is the topological cluster state a single-shot stabilizer code?

I believe this is just a matter of definition, in some sense the topological state is a single-shot code. One difference between the topological cluster state and single-shot 3D codes is that the size ...
• 1,714
1 vote
Accepted

Using Pymatching to decode lattice surgery process

There's nothing fundamentally different about getting pymatching to decode lattice surgery instead of memory. Make a stim circuit describing the exact operations that implement the surface codes being ...
• 40.6k
1 vote
Accepted

Which feedback is *necessary* for surface-code based and measurement based quantum computing?

That's right, a surface code computation that only performs Clifford gates can be performed without any feedback. Tracking the errors is sufficient to correct them. The corrections can be done ...
• 40.6k
1 vote
Accepted

perform a SWAP measurement using local operations and classical feedback

Measure SWAP from 7 CNOTs, linear connectivity, ancilla outside: (Note: improved this to not need any feedback anymore, and to just generally be cleaner.)
• 40.6k
1 vote
Accepted

Is this generalized 2D cluster state still a universal resource?

TLDR: Yes, it's universal. If you only measure on one of the two registers, No. Longer answer... Let's deal with the measuring just one register first. So we're doing nothing with the other register. ...
• 60.5k

Only top scored, non community-wiki answers of a minimum length are eligible