qdesignoptimizer.estimation.classical_model_decay_into_charge_line module
Analytical models for computing the decay of a mode in a transmsission line from the capacitance matrix.
- qdesignoptimizer.estimation.classical_model_decay_into_charge_line.mode_decay_rate_into_transmissionline(mode_freq_GHz: float, mode_capacitance_fF: float, coupling_capacitance_fF: float, impedance_env: float = 50) float[source]
Calculate the decay of a grounded mode into a charge line from a classical model for a single decay channel. Reference: Microwave photonics in superconducting circuits Appendix B Equation B.15.
- Parameters:
mode_freq_GHz (float) – (GHz) eigenfrequency of the oscillator or qubit transistion frequency.
mode_capacitance_fF (float) – (fF) The total capacitance of the mode.
coupling_capacitance_fF (float) – (fF) The capacitance between the mode and the charge line.
impedance_env (float) – (Ohm) The impedance of the charge line.
- Returns:
Decay rate to charge line (Hz).
- Return type:
- qdesignoptimizer.estimation.classical_model_decay_into_charge_line.calculate_t1_limit_grounded_lumped_mode_decay_into_chargeline(mode_freq_GHz: float, mode_capacitance_fF: float, mode_capacitance_to_charge_line_fF: float, charge_line_impedance: float = 50.0) float[source]
Wrapper around
mode_decay_rate_into_transmissionline()for the case of a grounded mode. In this case the coupling capacitance is just the capacitance between the single island and the charge line.- Parameters:
mode_freq_GHz (float) – (GHz) The frequency of the mode omega/2pi.
mode_capacitance_fF (float) – (fF) The total capacitance of the mode. The mode should be grounded such that its capacitance is constituted by a single capacitive pad.
mode_capacitance_to_charge_line_fF (float) – (fF) The capacitance between the mode and the charge line.
charge_line_impedance (float) – (Ohm) The impedance of the charge line.
- Returns:
The T1 limit due to decay into charge line decay (s).
- Return type:
- qdesignoptimizer.estimation.classical_model_decay_into_charge_line.calculate_t1_limit_floating_lumped_mode_decay_into_chargeline(mode_freq_GHz: float, cap_island_a_island_b_fF: float, cap_island_a_ground_fF: float, cap_island_a_line_fF: float, cap_island_b_ground_fF: float, cap_island_b_line_fF: float, charge_line_impedance: float = 50.0)[source]
Wrapper around
mode_decay_rate_into_transmissionline()for the case of a floating mode. In this case the coupling capacitance is an effective capacitance computed here from the capacitance newtork between two floating islands, a charge line and the ground plane.- Parameters:
mode_freq_GHz (float) – (GHz) The frequency of the mode omega/2pi.
cap_island_a_island_b_fF (float) – (fF) The capacitance across the junction from island B to island A.
cap_island_a_ground_fF (float) – (fF) The capacitance of island A to ground.
cap_island_b_ground_fF (float) – (fF) The capacitance of island B to ground.
cap_island_a_line_fF (float) – (fF) The coupling capacitance of the charge line to island A.
cap_island_b_line_fF (float) – (fF) The coupling capacitance of the charge line to island B.
charge_line_impedance (float) – (Ohm) The impedance of the charge line.
- Returns:
The T1 limit due to decay into charge line decay (s).
- Return type: