Unanswered Questions
327 questions with no upvoted or accepted answers
8
votes
0
answers
212
views
Optimal estimation of quantum state overlap - Circuit implementation?
I've been reading this paper, but don't understand what their optimal method really is, and how it can be realized as a quantum circuit.
The paper mentions the "Schur transform" which has a ...
- 433
8
votes
0
answers
295
views
What is a gate-level circuit used in the 2022 Jafferis et al. experiment on Sycamore?
A recently published Nature paper of Jafferis et al. describes an experiment with a handful of qubits performed on Google's Sycamore processor to explore the SYK model in the context of AdS/CFT and ...
- 14.4k
7
votes
0
answers
194
views
Sequential circuit using quantum gates
Without feedback/loop how can we build a sequential circuit? The basic feature of sequential circuit is that is depends not only on the current inputs but also on the previous inputs/outputs. I've ...
- 17.8k
6
votes
0
answers
143
views
How are Toffoli and a basis-changing single-qubit gate universal?
The Toffoli and Hadamard gates are universal for quantum computing: you can approximate any unitary up to arbitrary precision with a circuit built from these two gates. This is proved for example by ...
- 161
6
votes
0
answers
278
views
Quantum State Tomography Implementation in IBMQ
I am working to understand quantum state tomography, specifically using the algorithm presented in PRL 108, 070502. This paper is referenced in IBMQ implementations of QST, both in old deprecated ...
6
votes
0
answers
297
views
Could the Hamiltonian of a 2x2 Rubik's Cube be simulated with a NISQ device?
Consider the four cells on each of the six faces of the 2x2x2 Rubik's cube (the pocket cube). We can construct and simulate a quarter-turn Hamiltonian as below. $^*$
Let $\langle F_1,U_1,R_1\rangle$ ...
- 14.4k
6
votes
0
answers
132
views
Writing circuits in Qiskit using only Clifford and T gates
Is there a way in Qiskit to write my circuit using only Clifford and T gates (CX, S, H, T and I think also $S^\dagger$ and $T^\dagger$)? With the function compile (with aer simulator) it gives me some ...
- 3,469
6
votes
2
answers
215
views
Equivalence checking of quantum circuits up to error
Suppose you are given two circuit descriptions $A$ and $B$ where by a circuit description I mean a sequence of gates (in the order they are applied) and the qubits they are applied on. (For the sake ...
CommunityBot
- 1
6
votes
0
answers
141
views
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
votes
0
answers
151
views
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
89
views
Is circuit cutting equivalent in anyway to quantum teleportation?
I've been introduced recently to circuit cutting, and after seeing the 4 orthogonal measurements with their 8 corresponding initializations but no initial transfer of classical info, the first thing ...
5
votes
0
answers
88
views
What is the computational complexity of decomposing operators in terms of quantum gates?
I have recently worked on a problem involving a rather large Hamiltonian, which I wrote some Python code for its generation following the method in this paper.
No when I used qiskits ...
- 51
5
votes
0
answers
93
views
Arbitrary rotations in the plane spanned by two known quantum states
Suppose I have two quantum states $|\psi_1\rangle,|\psi_2\rangle$ that I know how to prepare from some fixed initial state, say $|0\rangle^{\otimes N}$ on some $N$ qubits with known quantum circuits $...
- 61.7k
5
votes
0
answers
271
views
How to get the compiled circuits and measurements from a Qiskit Runtime job
I have not been able to find any way to retrieve the compiled circuits and the measurement counts used for a Qiskit Runtime job. This page describes the various error suppression mechanisms available. ...
- 726
5
votes
0
answers
59
views
Is there a convention in quantum circuit diagrams for specific quantum measurements?
Is there a convention in quantum circuit diagrams for specific quantum measurements? For example, how could one express the measurement $|0\rangle \langle 0|$ in a circuit diagram?
glS♦
- 26.9k