Line data    Source code

       1             : # SPDX-FileCopyrightText: 2025 PairInteraction Developers
       2             : # SPDX-License-Identifier: LGPL-3.0-or-later
       3             : 
       4             : """Test calculating lifetimes."""
       5             : 
       6           1 : from __future__ import annotations
       7             : 
       8           1 : from typing import TYPE_CHECKING
       9             : 
      10           1 : import numpy as np
      11           1 : import pairinteraction as pi
      12           1 : import pytest
      13           1 : from pairinteraction import ureg
      14           1 : from scipy.optimize import curve_fit
      15             : 
      16             : if TYPE_CHECKING:
      17             :     from pairinteraction.units import NDArray
      18             : 
      19             : 
      20           1 : @pytest.mark.skip("The Yb174_mqdt database currently does not have low lying states.")
      21           1 : def test_lifetime() -> None:
      22             :     """Test calculating the lifetime of a state.
      23             : 
      24             :     Note that obtaining a reasonable value for the lifetime requires the full database and is not possible with the
      25             :     reduced database that is included in the repository!
      26             :     """
      27           0 :     ket = pi.KetAtom("Yb174_mqdt", n=64, l=0, j=0, m=0)
      28             : 
      29             :     # We use n=64 here, because this corresponds to nu~60 and we include
      30             :     # states with 50<nu<70 in the limited database that comes with the repository. In
      31             :     # addition, states with nu<20 are included so that the decay to the ground state
      32             :     # is also captured. Note that the relative error of the calculated
      33             :     # lifetime versus the actual lifetime is still quite large because of the limited
      34             :     # number of states. The full database is used and accurate results can be obtained
      35             :     # if the test is run with `pytest --database-dir "" --download-missing`.
      36             : 
      37           0 :     lifetime1 = ket.get_lifetime(temperature=300, temperature_unit="K", unit="us")
      38           0 :     lifetime2 = ket.get_lifetime(temperature=300 * ureg.K, unit="us")
      39           0 :     lifetime3 = ket.get_lifetime(temperature=300 * ureg.K)
      40           0 :     lifetime4 = ket.get_lifetime(unit="us")
      41             : 
      42           0 :     assert lifetime1 == lifetime2 == lifetime3.to(ureg.us).magnitude < lifetime4
      43           0 :     assert pytest.approx(lifetime1, rel=0.15) == 142.04845576112646  # NOSONAR
      44           0 :     assert pytest.approx(lifetime4, rel=0.15) == 494.1653414977515  # NOSONAR
      45             : 
      46             : 
      47           1 : def test_lifetime_scaling() -> None:
      48             :     """Test the scaling of the lifetime with the principal quantum number."""
      49             : 
      50           1 :     def fit_function(x: NDArray, a: float, b: float) -> NDArray:
      51           1 :         return a * x + b
      52             : 
      53           1 :     n_list = list(range(60, 70, 1))
      54             : 
      55             :     # S states
      56           1 :     kets = [pi.KetAtom("Rb", n=n, l=0, j=0.5, m=0.5) for n in n_list]
      57           1 :     nu = [ket.nu for ket in kets]
      58           1 :     lifetimes = [ket.get_lifetime(unit="us") for ket in kets]
      59           1 :     popt, _ = curve_fit(fit_function, np.log(nu), np.log(lifetimes))
      60           1 :     assert np.isclose(popt[0], 3, atol=0.02)
      61             : 
      62             :     # Circular states
      63           1 :     try:
      64           1 :         kets = [pi.KetAtom("Rb", n=n, l=n - 1, j=n - 0.5, m=n - 0.5) for n in n_list]
      65           1 :     except ValueError as err:
      66             :         # If the limited database which comes with the repository is used, creating the
      67             :         # kets will fail because the circular states are not included in the database.
      68             :         # This is expected.
      69           1 :         if "No state found" not in str(err):
      70           0 :             raise
      71             :     else:
      72           0 :         nu = [ket.nu for ket in kets]
      73           0 :         lifetimes = [ket.get_lifetime(unit="us") for ket in kets]
      74           0 :         popt, _ = curve_fit(fit_function, np.log(nu), np.log(lifetimes))
      75           0 :         assert np.isclose(popt[0], 5, atol=0.02)
      76             : 
      77             : 
      78           1 : def test_transition_rates() -> None:
      79             :     """Test calculating transition rates to other states.
      80             : 
      81             :     Note that obtaining a reasonable value for the transition rates requires the full database and is not possible
      82             :     with the reduced database that is included in the repository!
      83             :     """
      84           1 :     ket = pi.KetAtom("Yb174_mqdt", n=60, l=0, j=0, m=0)
      85             : 
      86           1 :     lifetime = ket.get_lifetime(temperature=300, temperature_unit="K", unit="us")
      87           1 :     kets_sp, rates_sp = ket.get_spontaneous_transition_rates(unit="MHz")
      88           1 :     kets_bbr, rates_bbr = ket.get_black_body_transition_rates(temperature=300, temperature_unit="K", unit="MHz")
      89             : 
      90           1 :     assert len(rates_sp) == len(kets_sp)
      91           1 :     assert len(rates_bbr) == len(kets_bbr)
      92           1 :     assert np.isclose(1 / (sum(rates_sp) + sum(rates_bbr)), lifetime)