dwave.system.temperatures.Ip_in_units_of_B#

Ip_in_units_of_B(Ip: None | float | ndarray = None, B: None | float | ndarray = 1.391, MAFM: float | None = 1.647, units_Ip: str | None = 'uA', units_B: Literal['GHz', 'J'] = 'GHz', units_MAFM: str | None = 'pH') → float | ndarray[source]#

Estimate qubit persistent current \(I_p(s)\) in schedule units.

Under a simple, noiseless freeze-out model, you can substitute flux biases for programmed linear biases, h, in the standard transverse-field Ising model as implemented on D-Wave quantum computers. Perturbations in h are not, however, equivalent to flux perturbations with respect to dynamics because of differences in the dependence on the anneal fraction, \(s\): \(I_p(s) \propto \sqrt(B(s))\). The physical origin of each term is different, and so precision and noise models also differ.

Assume a Hamiltonian in the documented form with an additional flux-bias-dependent component \(H(s) \Rightarrow H(s) - H_F(s) \sum_i \Phi_i \sigma^z_i\), where \(\Phi_i\) are flux biases (in units of \(\Phi_0\)), \(\sigma^z_i\) is the Pauli-z operator, and \(H_F(s) = Ip(s) \Phi_0\). Schedules for D-Wave quantum computers specify energy in units of Joule or GHz.

Parameters:

  • Ip – Persistent current, \(I_p(s)\), in units of amps or microamps. When not provided, inferred from \(M_{AFM}\) and and \(B(s)\) based on the relation \(B(s) = 2 M_{AFM} I_p(s)^2\).

  • B – Annealing schedule field, \(B(s)\), associated with the problem Hamiltonian. Schedules are provided for each quantum computer in the system documentation. This parameter is ignored when Ip is specified.

  • MAFM – Mutual inductance, \(M_{AFM}\), specified for each quantum computer in the system documentation. MAFM is ignored when Ip is specified.

  • units_Ip – Units in which the persistent current, Ip, is specified. Allowed values are 'uA' (microamps) and 'A' (amps)

  • units_B – Units in which the schedule B is specified. Allowed values are 'GHz' (gigahertz) and 'J' (Joules).

  • units_MAFM – Units in which the mutual inductance, MAFM, is specified. Allowed values are 'pH' (picohenry) and 'H' (Henry).

Returns:

\(I_p(s)\) with units matching the Hamiltonian \(B(s)\).