quchip.extensions.couplings

Reference coupling models with time dependence and coupling-owned loss.

Classes

CollectiveDecayCoupling(device_a, device_b)

Exchange coupling with an equal-phase collective decay channel.

ModulatedCapacitive(device_a, device_b[, ...])

Capacitive interaction with a prescribed sinusoidal strength variation.
class quchip.extensions.couplings.ModulatedCapacitive(device_a, device_b, static_strength=unbound, modulation_amplitude=unbound, modulation_frequency=unbound, modulation_phase=0.0, *, label=None)[source]

Bases: CouplingModel

Capacitive interaction with a prescribed sinusoidal strength variation.

The static term is \(g_0 n_a^{(q)}n_b^{(q)}\) and the modulation is \(\delta g\cos(2\pi\nu_m t+\phi_m)n_a^{(q)}n_b^{(q)}\).

Parameters:

  • device_a (device or str) – Coupled endpoints or their chip labels.

  • device_b (device or str) – Coupled endpoints or their chip labels.

  • static_strength (float) – Static capacitive strength \(g_0\) in GHz. Can be signed.

  • modulation_amplitude (float) – Modulation amplitude \(\delta g\) in GHz. Can be signed.

  • modulation_frequency (float) – Modulation frequency \(\nu_m\) in GHz. Must be positive.

  • modulation_phase (float, default 0.0) – Modulation phase in radians.

  • label (str or None, default None) – Coupling label.

static_strength: Any = Parameter(default=unbound, positive=False, nonnegative=False, serialize=True, unit='GHz', symbol='g_0', noise=False, kw_only=False, required=False)
modulation_amplitude: Any = Parameter(default=unbound, positive=False, nonnegative=False, serialize=True, unit='GHz', symbol='\\delta g', noise=False, kw_only=False, required=False)
modulation_frequency: Any = Parameter(default=unbound, positive=True, nonnegative=False, serialize=True, unit='GHz', symbol='\\nu_m', noise=False, kw_only=False, required=False)
modulation_phase: Any = Parameter(default=0.0, positive=False, nonnegative=False, serialize=True, unit='rad', symbol='\\phi_m', noise=False, kw_only=False, required=False)
interaction(a, b, p)[source]

Return the static capacitive interaction.

Parameters:
time_terms(a, b, p)[source]

Return the sinusoidally modulated capacitive interaction term.

Parameters:
class quchip.extensions.couplings.CollectiveDecayCoupling(device_a, device_b, exchange_strength=unbound, *, decay_rate=unbound, label=None)[source]

Bases: CouplingModel

Exchange coupling with an equal-phase collective decay channel.

Parameters:

  • device_a (device or str) – Coupled endpoints or their chip labels.

  • device_b (device or str) – Coupled endpoints or their chip labels.

  • exchange_strength (float) – Exchange rate \(g\) in GHz.

  • decay_rate (float) – Non-negative collective Lindblad rate \(\gamma_c\) in 1/ns.

  • label (str or None, default None) – Coupling label.

Notes

The collapse operator is proportional to a + b, a shared bath channel, not two independent relaxation channels.

exchange_strength: Any = Parameter(default=unbound, positive=False, nonnegative=False, serialize=True, unit='GHz', symbol='g', noise=False, kw_only=False, required=False)
decay_rate: Any = Parameter(default=unbound, positive=False, nonnegative=True, serialize=True, unit='1/ns', symbol='\\gamma_c', noise=True, kw_only=True, required=False)
interaction(a, b, p)[source]

Return the exchange interaction g(a b† + a† b).

Parameters:
dissipation(a, b, p)[source]

Return the shared-bath collapse channel proportional to a + b.

Parameters: