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Questions tagged [transmon]

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2 votes
0 answers
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Understanding Interaction in Cross Resonance Gates with Transmon Qubits

I have a question regarding the operation of 2-qubit gates. Two transmon qubits are coupled via a capacitor, and a microwave is applied to one of the transmons. The Hamiltonian for this setup can be ...
tare_'s user avatar
  • 51
6 votes
1 answer
121 views

Would an ambient-pressure, room-temperature superconductor eliminate the need for a dil-fridge in transmon processors?

Although there are many competing designs for quantum computer architectures, a transmon-based superconducting qubit architecture is well-advanced enough to be "in the lead" across various ...
1 vote
1 answer
80 views

Could you use $|0\rangle$ as excited state and $|1\rangle$ as ground state in transmon?

Why is the $|0\rangle$ state usually taken to be the ground state of a transmon qubit, and the $|1\rangle$ state the first excited state? Could you reverse this, and if so how would it affect the ...
Marc Bacvanski's user avatar
1 vote
0 answers
158 views

How to estimate the losses of a transmon qubit to its flux bias line

For transparency, I also posted this at the physics stackexchange, but it might be more fruitful to discuss here. Already in the original transmon paper by Koch et al. is it stated that while the ...
user129412's user avatar
1 vote
0 answers
23 views

How does superconductivity quantize the (non-)harmonic oscillator of the LC-circuit?

When reading literature on transmon, or in general charge, superconducting qubits the explanation usually starts from why two metallic islands with a bridge can be seen as LC-circuit, how that is a ...
qcabepsilon's user avatar
4 votes
0 answers
42 views

How and how much do fabrication defects affect superconducting qubit coherence time?

I used simulations to calculate T1 time of a transmon qubit, but the result is much longer than the lab data. I suspect it was because simulation does not consider fabrication defects. May I ask if ...
Hans's user avatar
  • 75
1 vote
0 answers
37 views

How relevant is quasiparticle tunneling noise to the T1 of a transmon?

I wish to check how much quasiparticle noise contributes to the relaxation of a transmon qubit since I need to use it for a project.
hlepsneder HCI's user avatar
2 votes
1 answer
566 views

What is the charge noise in the context of superconducting qubits?

I read from some papers that the charge noise is one of the factors that cause decoherence of qubits. May I know what charge noise is and how exactly the charge fluctuation affects the qubit frequency?...
Hans's user avatar
  • 75
0 votes
1 answer
113 views

Frequency range of superconducting qubit

What are the reasons/considerations for setting the transmon qubit frequency between around 3-6 GHz? What undesirable consequences will result if the frequency is out of the range?
Hans's user avatar
  • 75
2 votes
0 answers
48 views

When physically implementing superposition in a Transmon, what is the actual driving amplitude used in the microwave pulses by Qiskit?

I had been playing around with Qiskit Pulse, and I managed to run several single qubit circuits, however throughout these processes, I recurringly came across the driving amplitude and the signal ...
Aniket Chatterjee's user avatar
2 votes
1 answer
227 views

Why is there a frequency difference when performing ramsey experiment with setting neighbor qubits to different state?

For transmon qubits, there is an always-on zz interaction between coupled qubits, thus introducing static zz crosstalk. The figures are from this paper. I know zz crosstalk can change the frequency of ...
peachnuts's user avatar
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3 votes
0 answers
100 views

Individual processing of quantum circuit measurment results

When superconducting transmon qubits are measured with a readout pulse, the raw readout signal is demodulated, and results appear as clouds on the IQ plane, with one point in the cloud representing ...
psitae's user avatar
  • 1,340
6 votes
1 answer
694 views

In a transmon qubit, what corresponds to the ground and excited states?

In a transmon qubit, we have ground and energy eigenstates but what is actually happening in the circuit here? How do the current and voltage look? It looks like its made up of things you would find ...
snickers_stickers's user avatar