Coverage for jaxquantum / utils / units.py: 32%

1""" Units handling.""" 

2 

3 

4import scipy.constants as constants 

5import jax.numpy as np 

6 

7# Common Units 

8# ================================================================================================ 

9 

10FLUX_QUANTUM = constants.h / (2 * constants.e) 

11 

12 

13def GHz_to_joule(ghz): 

14 return ghz * 1e9 * constants.h 

15 

16 

17def joule_to_GHz(joule): 

18 return joule / (1e9 * constants.h) 

19 

20def n_thermal(frequency: float, temperature: float) -> float: 

21 """Calculate the average thermal photon number for a given frequency and temperature. 

22 

23 Args: 

24 frequency (float): Frequency in GHz. 

25 temperature (float): Temperature in Kelvin. 

26 

27 Returns: 

28 float: Average thermal photon number. 

29 """ 

30 k_B = constants.k # Boltzmann constant in J/K 

31 h = constants.h # Planck constant in J·s 

32 

33 exponent = h * (frequency * 1e9) / (k_B * temperature) 

34 n_avg = 1 / (np.exp(exponent) - 1) 

35 return n_avg 

36 

37 

38# Superconducting Qubit Unit Conversions 

39# ================================================================================================ 

40 

41FLUX_QUANTUM = constants.h / (2 * constants.e) 

42 

43 

44def inductive_energy_to_inductance(El): 

45 """Convert inductive energy E_L to inductance. 

46 

47 Args: 

48 El (float): inductive energy in GHz. 

49 

50 Returns: 

51 float: Inductance in nH. 

52 """ 

53 

54 inv_L = GHz_to_joule(El) * (2 * np.pi) ** 2 / (FLUX_QUANTUM**2) 

55 return 1e9 / inv_L 

56 

57def inductance_to_inductive_energy(L): 

58 """Convert inductance to inductive energy E_L. 

59 

60 Args: 

61 L (float): Inductance in nH. 

62 

63 Returns: 

64 float: Inductive energy in GHz. 

65 """ 

66 

67 inv_L = 1e9 / L 

68 El_joules = inv_L * (FLUX_QUANTUM**2) / (2 * np.pi) ** 2 

69 return joule_to_GHz(El_joules) 

70 

71 

72def inv_pF_to_Ec(inv_pfarad): 

73 """ 

74 1/picoFarad -> GHz 

75 """ 

76 inv_nFarad = inv_pfarad * 1e3 

77 Gjoule = (constants.e) ** 2 / (2) * inv_nFarad 

78 return joule_to_GHz(Gjoule * 1e9) 

79 

80 

81def Ec_to_inv_pF(Ec): 

82 """ 

83 GHz -> 1/picoFarad 

84 """ 

85 joule = GHz_to_joule(Ec) 

86 Gjoule = joule / 1e9 

87 inv_nFarad = Gjoule / ((constants.e) ** 2 / (2)) 

88 return inv_nFarad * 1e-3 

89 

90 

91def calculate_resonator_zpf(freq, impedance): 

92 expected_Z0 = impedance # Ohms 

93 expected_E_L_over_E_C = (1 / (4 * expected_Z0)) ** 2 * ( 

94 constants.h**2 / (8 * constants.e**4) 

95 ) 

96 desired_E_C = np.sqrt(freq**2 / expected_E_L_over_E_C / 8) 

97 desired_E_L = freq**2 / desired_E_C / 8 

98 storage_q_zpf = (1 / 32 * desired_E_L / desired_E_C) ** (1 / 4) 

99 

100 

101 # print((desired_E_L / desired_E_C), expected_E_L_over_E_C) 

102 

103 return storage_q_zpf, desired_E_C, desired_E_L