Unanswered Questions
429 questions with no upvoted or accepted answers
13
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308
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Is HHL still BQP-complete when the matrix entries are only in {0,1}?
I'm studying BQP-completeness proofs of a number of interesting problems of Janzing and Wocjan, and Wocjan and Zhang. Janzing and Wocjan show that estimating entries of matrix powers $(A^m)_{ij}$ with ...
- 12.4k
13
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0
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270
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Does the Curry-Howard correspondence have a quantum-specific type system?
In Wikipedia we can read that
the Curry–Howard correspondence is a correspondence between formal proof calculi and type systems for models of computation. In particular, it splits into two ...
- 3,342
11
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179
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Anti-symmetrization on the lattice
Assume, I'm using a system of qubits to simulate a fermionic system.
If I'm using the second-quantized formalism (e.g. orbitals in quantum chemistry), the anti-symmetric nature of the fermionic wave ...
- 2,221
8
votes
1
answer
410
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Enforcing a particular layout mapping in Qiskit
I would like to ask how to set a particular layout during transpiling. I guess that the layout can be set by the initial_layout parameter in the transpiler. However,...
CommunityBot
- 1
7
votes
0
answers
352
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Solving linear system $Ax=b$ with exponential speed-up via binary optimization?
The main disadvantage of HHL algorithm for solving $A|x\rangle = |b\rangle$ is that exponential speed-up is reached only in case we are interested in value $\langle x|M|x\rangle$, where $M$ is a ...
- 1
7
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0
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210
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Run VQE for parametrized quantum circuit with ancilla qubits
Let's say we have the following circuit (picture and code shown below), and now the $q_0$ is an ancilla qubit. If the system of interest has only two qubits, Is there a way to use only $q_{1,2}$ as my ...
glS♦
- 26.9k
6
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0
answers
132
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What is the largest linear system of equations solved using HHL experimentally?
Can someone tell what is the largest system of equations solved using HHL algorithm experimentally?
I know the $8$ x $8$ system has been solved experimentally. Has someone gone beyond this to solve $...
- 2,965
6
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141
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Bell State 11 not working for parity curve
I am currently writing a script to automate the creation of parity curves for a 2 qubit bell state and then calculate fidelity and proving entanglement from that (inspired by this paper). It was going ...
glS♦
- 26.9k
6
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0
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151
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How exactly is the stated composite state of the two registers being produced using the $R_{zz}$ controlled rotations?
This is a sequel to How are two different registers being used as "control"?
I found the following quantum circuit given in Fig 5 (page 6) of the same paper i.e. Quantum Circuit Design for ...
- 17.8k
5
votes
0
answers
122
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What is the classical cost of simulating an arbitrary quantum state?
The past couple of years has seen various groups claim quantum advantage/utility only to have their experiments efficiently simulated with classical methods, notably using tensor networks.
My question ...
glS♦
- 26.9k
5
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0
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662
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Add noise_model when using 'ibmq_qasm_simulator' backend and provider.runtime.run() function
I am trying to test some qiskit code that employs readout-error mitigation using the ibmq_qasm_simulator backend and Qiskit Runtime. I am getting the backend as ...
- 51
5
votes
1
answer
718
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Two qubit gate decomposition using Qiskit
I am writing some python code to be able to optimise the total error in two qubit gate decomposition.
I am using the Qiskit module qiskit.quantum_info.synthesis.two_qubit_decompose
My question relates ...
CommunityBot
- 1
5
votes
0
answers
158
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Trotter error for bosons in various encodings
Mapping second-quantized bosonic modes onto qubits can be done using various encodings. Each of those have their pro et contra. Fewer qubits — more gates, and vice versa. Encoding an $N$-level bosonic ...
- 2,438
5
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0
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71
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In the HHL algorithm, how large should the eigenvalue estimation register be?
In the HHL algorithm, we need to estimate the eigenvalues of a matrix $A$. The result is stored in a register with $l$ qubits. Let $T = 2^l$. $T$ cannot be too small, otherwise the result would have a ...
glS♦
- 26.9k
5
votes
0
answers
113
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What is the best way to use loop statements on a quantum computer?
I am interested in solving a time dependent linear partial differential equation of the form $Ax=b$ which, in classical computing, would amount to looping over solutions of $Ax=b$ where $b$ is updated ...
glS♦
- 26.9k