- Open Access
Geometric origin of the energy-momentum tensor improvement terms
Phys. Rev. D 112, 025007 – Published 8 July, 2025
DOI: https://doi.org/10.1103/wby2-d33f
Abstract
In a flat background, the canonical energy momentum tensor of Lorentz and conformally invariant matter field theories can be improved to a symmetric and traceless tensor that gives the same conserved charges. We argue that the geometric origin of this improvement process is unveiled when the matter theory is coupled to metric-affine gravity. In particular, we show that the Belinfante-Rosenfeld improvement terms correspond to the matter theory’s hypermomentum. The improvement terms in conformally invariant matter theories are also related to the hypermomentum; however, a general proof would require an extended investigation. We demonstrate our results through various examples, such as the free massless scalar, the Maxwell field, Abelian -forms, the Dirac field, and a nonunitary massless scalar field. Possible applications of our method for theories that break Lorentz or special conformal invariance are briefly discussed.
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References (52)
- F. J. Belinfante, On the current and the density of the electric charge, the energy, the linear momentum and the angular momentum of arbitrary fields, Physica 7, 449 (1940).
- L. Rosenfeld, Sur le tenseur d’impulsion-énergie, Mém. Acad. R. Belg. 18, 1 (1940), https://academieroyale.be/fr/publications-academie-toutes-publications-detail/oeuvres-2/sur-le-tenseur-d-impulsion-energie/.
- D. N. Blaschke, F. Gieres, M. Reboud, and M. Schweda, The energy–momentum tensor(s) in classical gauge theories, Nucl. Phys. B912, 192 (2016).
- J. Wess, The conformal invariance in quantum field theory, Nuovo Cimento 18, 1086 (1960).
- D. J. Gross and J. Wess, Scale invariance, conformal invariance, and the high-energy behavior of scattering amplitudes, Phys. Rev. D 2, 753 (1970).
- C. G. Callan, Jr., S. R. Coleman, and R. Jackiw, A new improved energy-momentum tensor, Ann. Phys. (N.Y.) 59, 42 (1970).
- F. W. Hehl, G. D. Kerlick, and P. Von der Heyde, On a new metric affine theory of gravitation, Phys. Lett. 63B, 446 (1976).
- F. W. Hehl, J. D. McCrea, E. W. Mielke, and Y. Ne’eman, Metric affine gauge theory of gravity: Field equations, Noether identities, world spinors, and breaking of dilation invariance, Phys. Rep. 258, 1 (1995).
- F. W. Hehl, G. D. Kerlick, and P. Von der Heyde, On hypermomentum in general relativity. 3. Coupling hypermomentum to geometry, Z. Naturforschr. A 31, 823 (1976).
- F. W. Hehl, E. A. Lord, and Y. Ne’eman, Hadron dilation, shear and spin as components of the intrinsic hypermomentum current and metric affine theory of gravitation, Phys. Lett. 71B, 432 (1977).
- D. Iosifidis and T. Koivisto, Scale transformations in metric-affine geometry, Universe 5, 82 (2019).
- S. Bahamonde, Y. Miyashita, and M. Yamaguchi, Trace anomaly in metric-affine gravity, Phys. Rev. D 111, 044065 (2025).
- J. Polchinski, Scale and conformal invariance in quantum field theory, Nucl. Phys. B303, 226 (1988).
- H. Osborn, Lecture notes on conformal field theories in more than two dimensions, available at http://www.damtp.cam.ac.uk/user/ho/ (to be published).
- T. Brauner, Noether currents of locally equivalent symmetries, Phys. Scr. 95, 035004 (2020).
- A. Freese, Noether’s theorems and the energy-momentum tensor in quantum gauge theories, Phys. Rev. D 106, 125012 (2022).
- I. Kourkoulou, A. Nicolis, and G. Sun, Improved Noether’s theorem for spacetime symmetries, Phys. Rev. D 106, 125005 (2022).
- F. Gieres, Improvement of a conserved current density versus adding a total derivative to a Lagrangian density, Fortschr. Phys. 70, 2200078 (2022).
- T. Kim and P. Yi, Lie, Noether, Kosmann, and diffeomorphism anomalies redux, arXiv:2412.03667.
- S. R. Coleman and R. Jackiw, Why dilatation generators do not generate dilatations?, Ann. Phys. (N.Y.) 67, 552 (1971).
- F. W. Hehl, J. D. McCrea, E. W. Mielke, and Y. Ne’eman, Progress in metric affine gauge theories of gravity with local scale invariance, Found. Phys. 19, 1075 (1989).
- R. Hecht, F. W. Hehl, J. D. McCrea, E. W. Mielke, and Y. Ne’eman, Improved energy momentum currents in metric affine space-time, Phys. Lett. A 172, 13 (1992).
- G. B. Folland, Weyl manifolds, J. Diff. Geom. 4, 145 (1970).
- G. Hall, Weyl manifolds and connections, J. Math. Phys. (N.Y.) 33, 2633 (1992).
- L. Ciambelli and R. G. Leigh, Weyl connections and their role in holography, Phys. Rev. D 101, 086020 (2020).
- H. T. Nieh, A spontaneously broken conformal gauge theory of gravitation, Phys. Lett. 88A, 388 (1982).
- Y. N. Obukhov, Conformal invariance and space-time torsion, Phys. Lett. 90A, 13 (1982).
- T. Dereli and R. W. Tucker, Weyl scalings and spinor matter interactions in scalar-tensor theories of gravitation, Phys. Lett. 110B, 206 (1982).
- D. Sauro and O. Zanusso, The origin of Weyl gauging in metric-affine theories, Classical Quantum Gravity 39, 185001 (2022).
- D. Sauro, R. Martini, and O. Zanusso, Projective transformations in metric-affine and Weylian geometries, Int. J. Geom. Methods Mod. Phys. 20, 2350237 (2023).
- Y. N. Obukhov and D. Puetzfeld, Conservation laws in gravity: A unified framework, Phys. Rev. D 90, 024004 (2014).
- D. Iosifidis, Cosmological hyperfluids, torsion and non-metricity, Eur. Phys. J. C 80, 1042 (2020).
- R. R. Lompay and A. N. Petrov, Covariant differential identities and conservation laws in metric-torsion theories of gravitation. I. General consideration, J. Math. Phys. (N.Y.) 54, 062504 (2013).
- R. R. Lompay and A. N. Petrov, Covariant differential identities and conservation laws in metric-torsion theories of gravitation. II. Manifestly generally covariant theories, J. Math. Phys. (N.Y.) 54, 102504 (2013).
- L. D. Landau and E. M. Lifschits, The Classical Theory of Fields (Pergamon Press, New York, 1975).
- Daniel Z. Freedman and Antoine Van Proeyen, Supergravity (Cambridge University Press, Cambridge, England, 2012).
- F. W. Hehl and B. K. Datta, Nonlinear spinor equation and asymmetric connection in general relativity, J. Math. Phys. (N.Y.) 12, 1334 (1971).
- F. W. Hehl, On the energy tensor of spinning massive matter in classical field theory and general relativity, Rep. Math. Phys. 9, 55 (1976).
- H. Osborn and A. Stergiou, for non-unitary CFTs in higher dimensions, J. High Energy Phys. 06 (2016) 079.
- C. T. Hill, Is the Higgs boson associated with Coleman-Weinberg dynamical symmetry breaking?, Phys. Rev. D 89, 073003 (2014).
- R. Aldrovandi and J. G. Pereira, Teleparallel gravity: An introduction, Fundam. Theor. Phys. 173, 171 (2013).
- D. Iosifidis, Quadratic metric-affine gravity: Solving for the affine-connection, Eur. Phys. J. C 82, 577 (2022).
- J. Erdmenger and H. Osborn, Conformally covariant differential operators: Symmetric tensor fields, Classical Quantum Gravity 15, 273 (1998).
- A. Stergiou, G. P. Vacca, and O. Zanusso, Weyl covariance and the energy momentum tensors of higher-derivative free conformal field theories, J. High Energy Phys. 06 (2022) 104.
- E. Kiritsis, Lorentz violation, gravity, dissipation and holography, J. High Energy Phys. 01 (2013) 030.
- J. de Boer, J. Hartong, N. A. Obers, W. Sybesma, and S. Vandoren, Perfect fluids, SciPost Phys. 5, 003 (2018).
- L. Ciambelli, C. Marteau, A. C. Petkou, P. M. Petropoulos, and K. Siampos, Covariant Galilean versus Carrollian hydrodynamics from relativistic fluids, Classical Quantum Gravity 35, 165001 (2018).
- J. de Boer, J. Hartong, E. Have, N. A. Obers, and W. Sybesma, Non-boost invariant fluid dynamics, SciPost Phys. 9, 018 (2020).
- A. C. Petkou, P. M. Petropoulos, D. R. Betancour, and K. Siampos, Relativistic fluids, hydrodynamic frames and their Galilean versus Carrollian avatars, J. High Energy Phys. 09 (2022) 162.
- J. de Boer, J. Hartong, N. A. Obers, W. Sybesma, and S. Vandoren, Carroll stories, J. High Energy Phys. 09 (2023) 148.
- D. Iosifidis, Metric-affine gravity and cosmology/aspects of torsion and non-metricity in gravity theories, arXiv:1902.09643.
- G. Munoz, Lagrangian field theories and energy-momentum tensors, Am. J. Phys. 64, 1153 (1996).