Unanswered Questions
330 questions with no upvoted or accepted answers
12
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0
answers
134
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Active improving of nanodiamond surfaces for NV centers?
This question is related (and complementary) to "Passive improving of nanodiamond surfaces for NV centers?".
Nitrogen-Vacancy centers (NVs) have astonishing quantum properties, which make them ...
glS♦
- 26.9k
9
votes
0
answers
374
views
Can you programatically check whether a given set of gates is universal?
I am wondering if there is an automated way to determine whether a given set of quantum operations is universal.
More precisely, given a set of 1 and 2 qubit gates, can we write a program to determine ...
- 1,225
8
votes
0
answers
295
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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
8
votes
0
answers
136
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Qubit fidelity of DWAVE device
Since DWAVE quantum device is constructed using superconducting flux qubits, each qubit cannot be produced identically so that the fidelity of the qubit must be different. DWAVE only provides the ...
- 397
8
votes
2
answers
749
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What design considerations set the frequency bounds for superconducting qubits?
Superconducting qubits generally have frequencies within the range of 4 - 8 GHz. What design considerations give the upper and lower bounds for what is a feasible design. I.e, why can't they be higher ...
CommunityBot
- 1
8
votes
0
answers
319
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What are the main obstacles to overcome to build silicon-photonic quantum computers?
In superconducting quantum computers, we use mostly superconducting qubits or trapped ions. However, those systems are quite large because their environment either requires near absolute zero ...
- 17.8k
8
votes
0
answers
382
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In D-Wave's universal quantum computer, why does the YY term have to be driven along with the linear X term?
D-Wave has a new prototype annealer that uses a Hamiltonian which, if there was enough qubits and sufficient control, would be able to simulate any universal circuit-based quantum computer with at ...
7
votes
0
answers
194
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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
154
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Universal gate set for the $ [[15,1,3]] $ code
The $ [[15,1,3]] $ triorthogonal code implements transversal $ T $. Since it is a CSS code, two blocks will also have a transversal $ CNOT $ gate. To get a universal gate set all that is required is ...
- 4,916
6
votes
0
answers
67
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Resources on the energy consumption of IBM quantum computers?
I am seeking information regarding the energy consumption of IBM Quantum Computers, specifically inquiring about the energy requirements associated with individual gate operations.
Could you also ...
glS♦
- 26.9k
6
votes
0
answers
251
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Solovay-Kitaev Balanced Group Commutators in SU(2) Implementation
I am currently looking into quantum compilation and came across Dawson and Nielsen's paper on the Solovay-Kitaev Algorithm, which seems like a good starting point as it is referenced in a many of the ...
- 101
6
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0
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132
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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
0
answers
144
views
Does Randomized Benchmarking characterize decoherence error?
In my understanding, Randomized Benchmarking (RB) generates a sequence of Clifford gates with different lengths and then characterizes the average error. Since RB is not sensitive to SPAM error, it ...
- 1,423
6
votes
0
answers
98
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Postselection and hardness of estimating amplitudes
Let $A$ be a class of quantum circuits such that
\begin{equation}
\text{Post}A = \text{Post}BQP,
\end{equation}
where $\text{Post}$ indicates post-selection. Is only this amount of information ...
- 1,515
6
votes
0
answers
135
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Is the universality of a qubit based quantum computer different from the universality of a continuous-variable quantum computer?
I understand that a quantum computer is universal if it can compute anything that a quantum Turing machine can. Another way to think about universality is that any unitary transformation on, e.g., a ...
glS♦
- 26.9k