Transmon Qubit Josephson Energy Calculator
Superconducting quantum information: Calculate transmon qubit charging energy ($E_C$), Josephson coupling energy ($E_J$), ratio ($E_J / E_C$), $0 \to 1$ transition frequency ($f_{01}$), and negative anharmonicity ($\alpha$).
Transmon Capacitance & Charging Energy
Junction + large shunt capacitor pads
Single electron charging energy e² / (2 C)
Josephson Junction Coupling
Tunnel junction critical current
Coupling energy Φ₀ Ic / (2π h)
Transmon Spectrum & Quantum Properties
Qubit Transition Frequency f_01:
--
GHz (Operating microwave resonance)
Anharmonicity α = f_12 - f_01:
--
MHz (Negative nonlinearity)
Ratio E_J / E_C:
--
Transmon regime: 50–100
Harmonic Plasma Frequency ω_p:
--
GHz (unperturbed LC oscillator)
| Second Transition Frequency f_12: | -- |
| Charge Dispersion Exponent: | -- |
| Zero-Point Phase Fluctuation rms: | -- |
| Quantum Circuit Classification: | -- |
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