Coverage for jaxquantum/devices/superconducting/tunable_transmon.py: 0%

1"""Tunable Transmon.""" 

2 

3from flax import struct 

4from jax import config 

5import jax.numpy as jnp 

6 

7from jaxquantum.devices.superconducting.transmon import Transmon 

8 

9config.update("jax_enable_x64", True) 

10 

11 

12@struct.dataclass 

13class TunableTransmon(Transmon): 

14 """ 

15 Tunable Transmon Device. 

16 """ 

17 

18 @property 

19 def Ej(self): 

20 Ejsum = self.params["Ej1"] + self.params["Ej2"] 

21 phi_ext = 2 * jnp.pi * self.params["phi_ext"] 

22 gamma = self.params["Ej2"] / self.params["Ej1"] 

23 d = (gamma - 1) / (gamma + 1) 

24 external_flux_factor = jnp.abs( 

25 jnp.sqrt(jnp.cos(phi_ext / 2) ** 2 + d**2 * jnp.sin(phi_ext / 2) ** 2) 

26 ) 

27 return Ejsum * external_flux_factor