Questions tagged [physical-qubit]

For questions related to physical realizations of quantum bits i.e. quantum systems living in a 2-dimensional Hilbert space.

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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 ...
4
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1answer
58 views

How do physical implementations of Z gate selectively affect $\lvert1\rangle $ basis vector?

The Pauli Z gate inverts the phase of $\lvert1\rangle $ while leaving $\lvert0\rangle$ unaffected. When I think about how $\lvert1\rangle $ and $\lvert0\rangle$ are physically realized, however, as ...
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155 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?
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27 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?
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0answers
48 views

I thought we had already passed this error and qubit threshold?

As outlined in Quantum Computing Progress and Prospects published this year, on page 169-171 there is the diagram showing that we are at the 10's of qubits mark. Looking into the diagram further there ...
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0answers
64 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)?
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67 views

What noise channel that is not coming from the control can lead to XY qubit rotations?

In a semiclassical treatment, the noise Hamiltonian of a quantum system can be treated as a summation over its noise channels in the following way: $$\hat{H}_{\text{noise}}=\sum_{k}\beta_{k}\left(t\...
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26 views

Can one make NV centred type qubits from analogus materials in the periodic table?

Can one replace Nitrogen with Phosphorus and Carbon with Silicon and so on? What would be the conditions that would preclude such a realisation? Are there any implemenations so far?
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Hamiltonian of the valence electron of Yb+ ion

Let's say I have chosen the valence electron of Yb+ as my qubit. I want to consider it's hyperfine structure as the two-level energy states. Are my following assumptions correct? If the magnetic ...
1
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1answer
32 views

Atom magnetic moment caused by orbiting electron

In Nielsen and Chuang Quantum Computation and Quantum Information book section 1.5.1 describing the Stern-Garlach experiment, it says: "Hydrogen atoms contain a proton and an orbiting electron. You ...
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37 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 ...
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0answers
56 views

Charge Qubit vs Transmon

I want to know the big difference, in terms of fabrication (circuit) between a charge Qubit and a Transmon, how is a Transmon less affected by noise ? Many thanks
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How much power do quantum computers use based on the number of qubits being allocated?

How much power do quantum computers use based on the number of qubits being allocated? If it's not based on qubits, What determines how much power quantum computers use? Note: A similar question was ...