Questions tagged [superconducting-quantum-computing]

For questions about the superconducting realization of quantum computers. Questions can be about both the implementation of this realization or the theory behind this realization. If you are asking about a specific aspect of superconducting quantum computers, please also tag with that (i.e., if you are also asking about the Josephson junction, tag with that).

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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
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1answer
91 views

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 ...
5
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0answers
112 views

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 ...
3
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0answers
42 views

Why are two qubits gates more noisy?

I would like to understand why two qubit gates are generally more noisy. If I am interested in single qubit gates, I can have an effective modelling as a master equation: $$\dot{\rho}=\frac{1}{i \...
3
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0answers
57 views

Is the theory of decoherence general or specific to the physical implementation?

I’m looking for the theoretical calculations of charge and transmon qubit decoherence specifically, but at a high level I'm wondering how decoherence is approached generally. I’ve seen explanations ...
3
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0answers
170 views

What is the charging energy in relation to a superconducting transmon?

The transmon achieves its reduced sensitivity to charge noise by significantly increasing the ratio of the Josephson energy to the charging energy. What is this charging energy?
2
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0answers
12 views

STO-3G Basis Set

Can someone please explain why STO-3G is considered to be a good basis set for quantum computing, while it does not help in classical computing? I would also be very grateful for any references to ...
2
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0answers
93 views

What is the difference between a cooper pair box and a transmon qubit?

These two kinds of qubits are both classified under "charge qubits", looking for them, I always find the same circuit representation. Occasionally, I find one where there's a SQUID instead of the ...
2
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0answers
30 views

Excitation of a superconducting circuit

What do we mean by exciting a superconducting circuit--which represent a qubit, how they are get excited inside? how the two states of the qubit are represented in this circuit?
2
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0answers
67 views

States of a qubit in a DC-SQUID

Does anybody of you know what are the two states $|0\rangle$ and $|1\rangle$ of a qubit in a DC-SQUID (2 Josephson junctions in a loop)?
1
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0answers
13 views

Many-photon limit of dispersive shift Hamiltionian

In the context of superconducting quantum computing measuments, consider the dispersive shift Hamiltonian: $$ H/\hbar = \omega_R a^\dagger a + \frac{1}{2} (\omega_Q + \frac{2g^2}{\Delta} a^\dagger a)\...
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11 views

Long range two qubit gates in superconducting qubits

In superconducting qubits, all the method that I have seen until now are based on short range interaction. For example you have two qubits to process information around a middle qubit that is ...
0
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0answers
17 views

Why does the relation between phase and flux hold true in an open segments of superconducting circuits?

This is what we write for a closed loop of superconducting circuit $$\Phi'\equiv\frac{m}{2n_p e^2}\oint_C \mathbf J\cdot d\mathbf r + \Phi_S=n\Phi_0,$$ which is usually converted to the form $\Phi'=\...