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Update mu_0, alpha to enforce consistency between constants #59

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Merged
merged 2 commits into from
Apr 2, 2025
Merged

Update mu_0, alpha to enforce consistency between constants #59

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2b4740d
Update mu_0, alpha to enforce consistency between constants
EZoni Apr 1, 2025
af30c54
Add comments to note differences from CODATA 2022
EZoni Apr 1, 2025
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9 changes: 7 additions & 2 deletions multi_physics/QED/QED_tests/test_picsar_phys_constants.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -50,10 +50,15 @@ void test_case_const_phys()
static_cast<RealType>(1.0545718176461565e-34);
const auto exp_vacuum_permittivity =
static_cast<RealType>(8.8541878188e-12);
// NOTE This is adjusted from the CODATA 2022 value 1.25663706127e-6,
// so that the relation between exp_light_speed, exp_vacuum_permittivity,
// and exp_vacuum_permeability is exact
const auto exp_vacuum_permeability =
static_cast<RealType>(1.25663706127e-6);
static_cast<RealType>(1.2566370612685e-6);
// NOTE This is calculated from alpha = mu_0/(4*pi)*q_e*q_e*c/hbar
// and differs slightly from the CODATA 2022 value 0.0072973525643
const auto exp_fine_structure =
static_cast<RealType>(0.0072973525643);
static_cast<RealType>(0.0072973525643330135);
const auto exp_eV =
static_cast<RealType>(1.602176634e-19);
const auto exp_KeV =
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11 changes: 8 additions & 3 deletions multi_physics/QED/include/picsar_qed/physics/phys_constants.h
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Original file line number Diff line number Diff line change
Expand Up @@ -27,11 +27,16 @@ namespace picsar::multi_physics::phys
template<typename RealType = double>
constexpr auto vacuum_permittivity = RealType(8.8541878188e-12);

// NOTE This is adjusted from the CODATA 2022 value 1.25663706127e-6,
// so that the relation between exp_light_speed, exp_vacuum_permittivity,
// and exp_vacuum_permeability is exact
template<typename RealType = double>
constexpr auto vacuum_permeability = RealType(1.25663706127e-6);
constexpr auto vacuum_permeability = RealType(1.2566370612685e-6);

// NOTE This is calculated from alpha = mu_0/(4*pi)*q_e*q_e*c/hbar
// and differs slightly from the CODATA 2022 value 0.0072973525643
template<typename RealType = double>
constexpr auto fine_structure = RealType(0.0072973525643);
constexpr auto fine_structure = RealType(0.0072973525643330135);

template<typename RealType = double>
constexpr auto eV = RealType(elementary_charge<>);
Expand All @@ -52,7 +57,7 @@ namespace picsar::multi_physics::phys
//(unfortunately, sqrt is not constexpr)
template<typename RealType = double>
constexpr auto sqrt_4_pi_fine_structure =
RealType(0.3028221207683449);
RealType(0.3028221207690299);
Comment on lines 57 to +60
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@EZoni EZoni Apr 1, 2025

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Please double check this too, since it is hard coded.


//
template<typename RealType = double>
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