Does an electromagnetic field affect neutral particles via the metric because of the EM stress-energy tensor?

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I'm just starting to learn general relativity (GR), and I'm a beginner, but I came out with this situation which is unclear to me: The trajectory of a charged particle in GR is given from the equation:



$$dotu^mu + Gamma^mu_alpha beta u^alpha u^beta = fracqm F^mu_; nu , u^nu$$



So, if I have a neutral particle $q=0$ the equation reduces to the geodesic equation for a free particle, but because of the Einstein-Maxwell equations:



$$R_mu nu - frac12 R g_mu nu = T^EM_mu nu$$



the EM stress-energy tensor determines the form of the metric, and consequently the Christoffel symbols that appears in the geodesic equation for the neutral particle. So would the trajectory of this neutral particle in an EM field be different from the case of a space-time with a null EM field?







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    up vote
    12
    down vote

    favorite
    2












    I'm just starting to learn general relativity (GR), and I'm a beginner, but I came out with this situation which is unclear to me: The trajectory of a charged particle in GR is given from the equation:



    $$dotu^mu + Gamma^mu_alpha beta u^alpha u^beta = fracqm F^mu_; nu , u^nu$$



    So, if I have a neutral particle $q=0$ the equation reduces to the geodesic equation for a free particle, but because of the Einstein-Maxwell equations:



    $$R_mu nu - frac12 R g_mu nu = T^EM_mu nu$$



    the EM stress-energy tensor determines the form of the metric, and consequently the Christoffel symbols that appears in the geodesic equation for the neutral particle. So would the trajectory of this neutral particle in an EM field be different from the case of a space-time with a null EM field?







    share|cite|improve this question
























      up vote
      12
      down vote

      favorite
      2









      up vote
      12
      down vote

      favorite
      2






      2





      I'm just starting to learn general relativity (GR), and I'm a beginner, but I came out with this situation which is unclear to me: The trajectory of a charged particle in GR is given from the equation:



      $$dotu^mu + Gamma^mu_alpha beta u^alpha u^beta = fracqm F^mu_; nu , u^nu$$



      So, if I have a neutral particle $q=0$ the equation reduces to the geodesic equation for a free particle, but because of the Einstein-Maxwell equations:



      $$R_mu nu - frac12 R g_mu nu = T^EM_mu nu$$



      the EM stress-energy tensor determines the form of the metric, and consequently the Christoffel symbols that appears in the geodesic equation for the neutral particle. So would the trajectory of this neutral particle in an EM field be different from the case of a space-time with a null EM field?







      share|cite|improve this question














      I'm just starting to learn general relativity (GR), and I'm a beginner, but I came out with this situation which is unclear to me: The trajectory of a charged particle in GR is given from the equation:



      $$dotu^mu + Gamma^mu_alpha beta u^alpha u^beta = fracqm F^mu_; nu , u^nu$$



      So, if I have a neutral particle $q=0$ the equation reduces to the geodesic equation for a free particle, but because of the Einstein-Maxwell equations:



      $$R_mu nu - frac12 R g_mu nu = T^EM_mu nu$$



      the EM stress-energy tensor determines the form of the metric, and consequently the Christoffel symbols that appears in the geodesic equation for the neutral particle. So would the trajectory of this neutral particle in an EM field be different from the case of a space-time with a null EM field?









      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Aug 19 at 9:40









      Peter Mortensen

      1,87811223




      1,87811223










      asked Aug 19 at 0:28









      Julian Ar.

      3291210




      3291210




















          2 Answers
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          The answer to your question is yes, the metric is influenced by the electromagnetic field, and a neutral particle will follow a geodesic of that metric. Thus, this implies that the neutral particle will indeed "feel" the electromagnetic field, but only in a very indirect way (from the geometry of spacetime around the particle).



          The best example of this is the Reissner-Nordström metric, which is a generalisation of the Schwarzschild metric, in case a radial electrostatic field is present in vacuum.



          Gravity is universal. It affects everything that has energy-momentum, and electromagnetic fields do have energy-momentum. So spacetime is "deformed" (i.e. curved) by the electromagnetic field, and since matter (or any field) moves in that spacetime, the motion is influenced by the content of spacetime.






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            Yes, this is not only possible but ubiquitous. A portion of the Earth’s mass is due to electromagnetic field energy in the atoms that make it up. You feel the gravity due to this mass constantly. The fact that all mass-energy contributes to gravity is just the (strong) equivalence principle, which is obeyed by GR.






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              2 Answers
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              active

              oldest

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              2 Answers
              2






              active

              oldest

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              active

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              active

              oldest

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              up vote
              11
              down vote



              accepted










              The answer to your question is yes, the metric is influenced by the electromagnetic field, and a neutral particle will follow a geodesic of that metric. Thus, this implies that the neutral particle will indeed "feel" the electromagnetic field, but only in a very indirect way (from the geometry of spacetime around the particle).



              The best example of this is the Reissner-Nordström metric, which is a generalisation of the Schwarzschild metric, in case a radial electrostatic field is present in vacuum.



              Gravity is universal. It affects everything that has energy-momentum, and electromagnetic fields do have energy-momentum. So spacetime is "deformed" (i.e. curved) by the electromagnetic field, and since matter (or any field) moves in that spacetime, the motion is influenced by the content of spacetime.






              share|cite|improve this answer


























                up vote
                11
                down vote



                accepted










                The answer to your question is yes, the metric is influenced by the electromagnetic field, and a neutral particle will follow a geodesic of that metric. Thus, this implies that the neutral particle will indeed "feel" the electromagnetic field, but only in a very indirect way (from the geometry of spacetime around the particle).



                The best example of this is the Reissner-Nordström metric, which is a generalisation of the Schwarzschild metric, in case a radial electrostatic field is present in vacuum.



                Gravity is universal. It affects everything that has energy-momentum, and electromagnetic fields do have energy-momentum. So spacetime is "deformed" (i.e. curved) by the electromagnetic field, and since matter (or any field) moves in that spacetime, the motion is influenced by the content of spacetime.






                share|cite|improve this answer
























                  up vote
                  11
                  down vote



                  accepted







                  up vote
                  11
                  down vote



                  accepted






                  The answer to your question is yes, the metric is influenced by the electromagnetic field, and a neutral particle will follow a geodesic of that metric. Thus, this implies that the neutral particle will indeed "feel" the electromagnetic field, but only in a very indirect way (from the geometry of spacetime around the particle).



                  The best example of this is the Reissner-Nordström metric, which is a generalisation of the Schwarzschild metric, in case a radial electrostatic field is present in vacuum.



                  Gravity is universal. It affects everything that has energy-momentum, and electromagnetic fields do have energy-momentum. So spacetime is "deformed" (i.e. curved) by the electromagnetic field, and since matter (or any field) moves in that spacetime, the motion is influenced by the content of spacetime.






                  share|cite|improve this answer














                  The answer to your question is yes, the metric is influenced by the electromagnetic field, and a neutral particle will follow a geodesic of that metric. Thus, this implies that the neutral particle will indeed "feel" the electromagnetic field, but only in a very indirect way (from the geometry of spacetime around the particle).



                  The best example of this is the Reissner-Nordström metric, which is a generalisation of the Schwarzschild metric, in case a radial electrostatic field is present in vacuum.



                  Gravity is universal. It affects everything that has energy-momentum, and electromagnetic fields do have energy-momentum. So spacetime is "deformed" (i.e. curved) by the electromagnetic field, and since matter (or any field) moves in that spacetime, the motion is influenced by the content of spacetime.







                  share|cite|improve this answer














                  share|cite|improve this answer



                  share|cite|improve this answer








                  edited Aug 19 at 10:46









                  Jens

                  2,38611431




                  2,38611431










                  answered Aug 19 at 2:21









                  Someone

                  1,16611029




                  1,16611029




















                      up vote
                      4
                      down vote













                      Yes, this is not only possible but ubiquitous. A portion of the Earth’s mass is due to electromagnetic field energy in the atoms that make it up. You feel the gravity due to this mass constantly. The fact that all mass-energy contributes to gravity is just the (strong) equivalence principle, which is obeyed by GR.






                      share|cite|improve this answer
























                        up vote
                        4
                        down vote













                        Yes, this is not only possible but ubiquitous. A portion of the Earth’s mass is due to electromagnetic field energy in the atoms that make it up. You feel the gravity due to this mass constantly. The fact that all mass-energy contributes to gravity is just the (strong) equivalence principle, which is obeyed by GR.






                        share|cite|improve this answer






















                          up vote
                          4
                          down vote










                          up vote
                          4
                          down vote









                          Yes, this is not only possible but ubiquitous. A portion of the Earth’s mass is due to electromagnetic field energy in the atoms that make it up. You feel the gravity due to this mass constantly. The fact that all mass-energy contributes to gravity is just the (strong) equivalence principle, which is obeyed by GR.






                          share|cite|improve this answer












                          Yes, this is not only possible but ubiquitous. A portion of the Earth’s mass is due to electromagnetic field energy in the atoms that make it up. You feel the gravity due to this mass constantly. The fact that all mass-energy contributes to gravity is just the (strong) equivalence principle, which is obeyed by GR.







                          share|cite|improve this answer












                          share|cite|improve this answer



                          share|cite|improve this answer










                          answered Aug 19 at 3:28









                          knzhou

                          33.4k897167




                          33.4k897167



























                               

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