Unanswered Questions
79 questions with no upvoted or accepted answers
12
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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
8
votes
0
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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
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0
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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
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2
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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
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0
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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
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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 ...
5
votes
0
answers
188
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How do we realise photonic gates?
I am interested in photonic computing, and I am curious how the gates work. I once saw a picture of a photonic CNOT gate that used just mirrors and polarizers. I have not been able to find any ...
glS♦
- 26.9k
5
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0
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94
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Are single photons necessary for this quantum autoencoder implementation?
The following diagram is from Experimental Realization of a Quantum Autoencoder: The Compression of Qutrits via Machine Learning
How this setup works:
What will be obtained from this set up is the ...
- 437
4
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0
answers
74
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When is a quantum algorithm considered to have a significantly superior performance over another quantum algorithm?
Suppose we have two heuristic quantum algorithms $A$ and $B$ that attempt to solve a certain class of optimization problems. Let's suppose that the benchmarking metric is Time To Solution (TTS), which ...
glS♦
- 26.9k
4
votes
0
answers
185
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Probability of error in BB84 if Eve is using Breidbart's basis
I'm taking a course on quantum cryptography and I have a homework to calculate probability of error in BB84.
The task says to assume that Eve uses the Breidbart basis with eigenvectors $$|φ_0⟩ = \cos(...
- 2,396
4
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0
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265
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What are currently the best reported qubit error rates per gate operation?
Based on some investigation, I have found the best qubit coherence timescales, in superconducting architectures, to be the order of milliseconds.
https://journals.aps.org/prb/abstract/10.1103/PhysRevB....
- 2,396
4
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0
answers
69
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How are measurements done exactly on IBM cloud computers?
A quantum cloud server like from IBM typically returns a string of 0's and 1's such as 0010.
How is this measurement done exactly? I realize that the IBM cloud computers are transmon devices based on ...
glS♦
- 26.9k
4
votes
0
answers
125
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Why is it important to perform optical quantum computing with ONLY linear components?
The main achievement of the KLM protocol is demonstrating that quantum computing can be done with only linear optical elements, i.e., beam splitters, phase shifters, single-photon sources, and photo-...
- 2,396
4
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0
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251
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How to design a RF-SQUID qubit by Qiskit Metal?
I am now learning how to use Qiskit Metal to design superconducting circuits. I found that there are only several transmon qubits in the library. Can I design an RF-SQUID qubit by using Qiskit metal?
...
CommunityBot
- 1
4
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0
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71
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What type of tasks it is possible to solve on a quantum simulator?
In this article, the author claimed that researches from Harvard and MIT created 256 qubits quantum simulator. However, we are not talking about piece of software on a classical computer but actual ...
- 14.9k