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