This is an unedited manuscript accepted for publication and provided as an Article in Press for early access at the author’s request. The article will undergo copyediting, typesetting, and galley proof review before final publication. Please be aware that errors may be identified during production that could affect the content. All legal disclaimers of the journal apply.
vaidik A sharma,
N. Madurai Meenachi2,
- Student, Department of Physics ,Birla Institute of Technology, Rajasthan, India
- Scientific officer, Indira Gandhi Centre for Atomic Research, Kalpakkam, India
Abstract
This paper provides an in-depth analysis of entanglement entropy (EE) in quantum field theory (QFT), with a particular focus on its computation using the replica trick and its applications to both conformal and non-conformal systems. Beginning with an introduction to the basics of QFT, the study explains how entanglement entropy quantifies the quantum correlations between subsystems in a pure state, represented by the von Neumann entropy of the reduced density matrix. The replica trick is employed to derive the entanglement entropy, involving path integrals over n-sheeted Riemann surfaces. The paper demonstrates the method’s utility in 1+1-dimensional conformal field theory (CFT), where the central charge governs universal properties of entropy. It further extends the analysis to massive field theories, finite systems, and topological phases, exploring how deviations from conformal symmetry affect entanglement. The work also delves into the AdS/CFT correspondence, showcasing how holographic techniques facilitate entanglement entropy calculations in higher-dimensional systems via the Ryu-Takayanagi formula. In addition, the study investigates entanglement entropy in quantum lattice systems, considering the effects of spatial and thermal fluctuations. Numerical methods are used to compute the scaling of entanglement entropy with interval length for varying system masses and temperatures, highlighting the influence of these parameters on entropy behavior. Fractal lattice structures are explored to uncover unique entropy scaling laws and self-similar entanglement patterns. This study advances the under-standing of EE in diverse quantum systems and establishes a foundation for exploring its role in quantum criticality and fractal geometries. The paper also explores multiscale entanglement entropy (MSE), offering a comprehensive framework for future research in quantum critical phenomena and non-equilibrium systems, shedding light on the complex relationship between quantum entanglement and thermal effects. This work serves as a foundational reference for future theoretical and computational studies in quantum entanglement
Keywords: Entanglement Entropy, Quantum Field Theory, Conformal Field Theory, AdS/CFT Correspondence, Holographic Principle, String Theory, Quantum Gravity
vaidik A sharma, N. Madurai Meenachi2. Comprehensive study of Entanglement Entropy in Quantum Field Theory: Analysis of Conformal Field Theory to Massive Field Extensions and Holographic Entanglement. Research & Reviews : Journal of Physics. 2025; ():-.
vaidik A sharma, N. Madurai Meenachi2. Comprehensive study of Entanglement Entropy in Quantum Field Theory: Analysis of Conformal Field Theory to Massive Field Extensions and Holographic Entanglement. Research & Reviews : Journal of Physics. 2025; ():-. Available from: https://journals.stmjournals.com/rrjophy/article=2025/view=0
References
- Calabrese and J. Cardy, “Entanglement Entropy and Quantum Field Theory,” J. Stat. Mech., vol. 2004, P06002, 2004.
- Holzhey, F. Larsen, and F. Wilczek, “Geometric and Renormalized Entropy in Conformal Field Theory,” Nucl. Phys. B, vol. 424, pp. 443-467, 1994.
- Ryu and T. Takayanagi, “Holographic Entanglement Entropy,” Phys. Rev. Lett., vol. 96, no. 18, p. 181602, 2006.
- A. Castro-Alvaredo and L. Santamarıa-Sanz, “Symmetry Re-solved Measures in Quantum Field Theory: a Short Review,” 2024, arXiv preprint, arXiv:2403.06652. Available at: https://arxiv.org/abs/2403. 06652.
- Prescod-Weinstein and E. Bertschinger, ”An extension of the Faddeev–Jackiw technique to fields in curved spacetimes,” Classi-cal and Quantum Gravity 32, 7, 075011 (2015), doi:10.1088/0264-9381/32/7/075011.
- Daniel Azses, David F. Mross, and Eran Sela, “Symmetry-resolved entanglement of two-dimensional symmetry-protected topological states,” Physical Review B, vol. 107, no. 11, p. 115113, 2023. doi:10.1103/PhysRevB.107.115113.
- Piroli and E. Vernier, “Entanglement Hamiltonians in the Schwinger model,” 2024, arXiv preprint, arXiv:2403.08091. Available at: https: //arxiv.org/abs/2403.08091.
- E. Aguilar-Gutierrez, “De Sitter space, complexity, and the double-scaled SYK model,” 2024, arXiv preprint, arXiv:2406.19089. Available at: https://arxiv.org/abs/2406.19089.
- B. Chen, “Quantum entanglement dynamics of spacetime and matter,” Fundamental Research, 2023. Available at: https://www.sciencedirect. com/science/article/pii/S2667325823002819.
- Kudler-Flam, S. Leutheusser, and A. A. Rahman, “A covariant regula-tor for entanglement entropy: Proofs of the Bekenstein bound and QNEC,” arXiv preprint, 2023. Available at: https://arxiv.org/abs/2312.07646.
- H. Mo, Y. Zhou, J. R. Sun, and P. Ye, “Hyperfine Structure of Quantum Entanglement,” arXiv preprint, 2024. Available at: https://arxiv. org/abs/2311.01997.
- Melnikov, “Connectomes as holographic states,” arXiv preprint, 2023. Available at: https://arxiv.org/abs/2312.16683.
- A. Roa Rodrıguez, “On entanglement entropy in quantum field theory,” 2023. Available at: https://repositorio.uniandes.edu.co/bitstreams/ 57aaa9c4-be57-4089-9f36-71140c690fca/download.
- Meng, ”An Introduction to Embedding-Based Retrieval,” [Online]. Available: https://www.yuan-meng.com/posts/ebr/.
- Rabideau, ”Perturbative entanglement entropy in nonlocal theories,” Journal of High Energy Physics 2015, no. 9, 180 (2015), SISSA, Springer, doi:10.1007/JHEP09(2015)180.
- Casini and M. Huerta, “Entanglement entropy in free quantum field theory,” J. Phys. A: Math. Theor., vol. 42, no. 50, p. 504007, 2009.
- Bombelli, J. Lee, D. Meyer, and R. D. Sorkin, “Space-time as a causal set,” Phys. Rev. Lett., vol. 59, no. 5, pp. 521–524, Aug. 1987, 10.1103/PhysRevLett.59.521. Available: https://link.aps.org/doi/10.1103/ PhysRevLett.59.521.
- Susskind, “The world as a hologram,” J. Math. Phys., vol. 36, no. 11, pp. 6377–6396, 1995.
- Banados, C. Teitelboim, and J. Zanelli, “Black hole in three-dimensional spacetime,” Phys. Rev. Lett., vol. 69, no. 13, pp. 1849–1851, Sep. 1992, 10.1103/PhysRevLett.69.1849. Available: http://dx.doi.org/10. 1103/PhysRevLett.69.1849.
- Faulkner, A. Lewkowycz, and J. Maldacena, “Quantum corrections to holographic entanglement entropy,” J. High Energy Phys., vol. 2013, no. 11, p. 074, Nov. 2013, 10.1007/JHEP11(2013)074. Available: http: //dx.doi.org/10.1007/JHEP11(2013)074.
- A. Metlitski, C. A. Fuertes, and S. Sachdev, “Entanglement entropy in the O(N) model,” Phys. Rev. B, vol. 80, no. 11, p. 115122, Sep. 2009, 10.1103/PhysRevB.80.115122. Available: https://link.aps.org/doi/ 10.1103/PhysRevB.80.115122.
- Heemskerk, J. Penedones, J. Polchinski, and J. Sully, “Holography from conformal field theory,” Journal of High Energy Physics, vol. 2009, no. 10, p. 079, Oct. 2009, 10.1088/1126-6708/2009/10/079. Available: http://dx.doi.org/10.1088/1126-6708/2009/10/079.
- Banks and W. Fischler, “An Holographic Cosmology,” 2001, arXiv preprint, arXiv:hep-th/0111142. Available: https://arxiv.org/abs/hep-th/ 0111142.
- Steven Weinberg, “Fluctuations in the cosmic microwave background. II. C at large and small l,” Phys. Rev. D, vol. 64, no. 12, p. 123512, Nov. 2001. doi: 10.1103/PhysRevD.64.123512. Available: https://link.aps.org/ doi/10.1103/PhysRevD.64.123512.
- Hartman and J. Maldacena, “Time evolution of entanglement entropy from a CFT perspective,” J. High Energy Phys., vol. 2013, no. 5, p. 014, 2013.
- Vidal, J. I. Latorre, E. Rico, and A. Kitaev, “Entanglement in Quan-tum Critical Phenomena,” Phys. Rev. Lett., vol. 90, no. 22, p. 227902, Jun. 2003. doi: 10.1103/PhysRevLett.90.227902. Available: https://link. aps.org/doi/10.1103/PhysRevLett.90.227902.
- Aguado and G. Vidal, “Entanglement Renormalization and Topo-logical Order,” Phys. Rev. Lett., vol. 100, no. 7, p. 070404, Feb. 2008. doi: 10.1103/PhysRevLett.100.070404. Available: https://link.aps.org/doi/ 10.1103/PhysRevLett.100.070404.
- Sayahian Jahromi, S.A. Moosavi, H. Moradpour, J.P. Morais Grac¸a, I.P. Lobo, I.G. Salako, and A. Jawad, “Generalized entropy formalism and a new holographic dark energy model,” Phys. Lett. B, vol. 780, pp. 21–24, May 2018. doi: 10.1016/j.physletb.2018.02.052. Available: http: //dx.doi.org/10.1016/j.physletb.2018.02.052.
- Iso, T. Mori, and K. Sakai, “Entanglement entropy in scalar field theory and ZM gauge theory on Feynman diagrams,” Phys. Rev. D, vol. 103, no. 10, p. 105010, May 2021. doi: 10.1103/PhysRevD.103.105010. Available: https://link.aps.org/doi/10.1103/PhysRevD.103.105010.
- Halawani, “Entanglement Entropy and Algebra in Quantum Field Theory,” 2023, arXiv preprint, arXiv:2307.06286. Available: https://arxiv. org/abs/2307.06286.
- Hollands and K. Sanders, Entanglement Measures and Their Prop-erties in Quantum Field Theory, vol. 34, Berlin/Heidelberg, Germany: Springer, 2018.
- A. Sharma, “Gauge Theories, Diagrammatics, and Algebra in Quan-tum Field Theory: A Detailed Analysis,” A¡ A, vol. 2, no. 3, 2024.
- N. Solodukhin, “Entanglement entropy in non-relativistic field theo-ries,” J. High Energy Phys., vol. 2010, no. 4, pp. 1-10, 2010.
- Kitaev and J. Preskill, “Topological entanglement entropy,” Phys. Rev. Lett., vol. 96, no. 11, p. 110404, 2006.
- Pretko, “On the entanglement entropy of Maxwell theory: a con-densed matter perspective,” J. High Energy Phys., vol. 2018, no. 12, pp. 1-24, 2018.
- Boyanovsky, “Information loss in effective field theory: entanglement and thermal entropies,” Phys. Rev. D, vol. 97, no. 6, p. 065008, 2018.
- Eling, Y. Oz, and S. Theisen, “Entanglement and thermal entropy of gauge fields,” J. High Energy Phys., vol. 2013, no. 11, pp. 1-14, 2013.
- Swingle and T. Senthil, “Universal crossovers between entanglement entropy and thermal entropy,” Phys. Rev. B, vol. 87, no. 4, p. 045123, 2013.
- Berges, S. Floerchinger, and R. Venugopalan, “Dynamics of entan-glement in expanding quantum fields,” J. High Energy Phys., vol. 2018, no. 4, pp. 1-45, 2018.
- Headrick, “Lectures on entanglement entropy in field theory and holography,” arXiv preprint, arXiv:1907.08126, 2019.
- Eisert, M. Cramer, and M. B. Plenio, “Area laws for the entanglement entropy-a review,” arXiv preprint, arXiv:0808.3773, 2008.
- B. Fel’dman and M. A. Yurishchev, “Fluctuations of quantum entanglement,” JETP Letters, vol. 90, pp. 70-74, 2009.
- Kabat, “Black hole entropy and entropy of entanglement,” Nuclear Physics B, vol. 453, no. 1-2, pp. 281-299, 1995.
- Jensen and A. O’Bannon, “Holography, entanglement entropy, and conformal field theories with boundaries or defects,” Physical Review D—Particles, Fields, Gravitation, and Cosmology, vol. 88, no. 10, p. 106006, 2013.
- He, T. Numasawa, T. Takayanagi, and K. Watanabe, “Notes on entanglement entropy in string theory,” Journal of High Energy Physics, vol. 2015, no. 5, pp. 1-27, 2015.
- V. Fursaev, “Quantum entanglement on boundaries,” Journal of High Energy Physics, vol. 2013, no. 7, pp. 1-25, 2013.
- Berges, S. Floerchinger, and R. Venugopalan, “Thermal excitation spectrum from entanglement in an expanding quantum string,” Physics Letters B, vol. 778, pp. 442-446, 2018.
- Haldar, S. Bera, and S. Banerjee, “Renyi entanglement entropy of Fermi and non-Fermi liquids: Sachdev-Ye-Kitaev model and dynamical mean field theories,” Physical Review Research, vol. 2, no. 3, p. 033505, 2020.
- Dong, X. L. Qi, Shangnan Z., and Z. Yang, “Effective entropy of quantum fields coupled with gravity,” Journal of High Energy Physics, vol. 2020, no. 10, pp. 1-52, 2020.
- Wen, S. Ryu, and A. W. Ludwig, “Entanglement hamiltonian evolu-tion during thermalization in conformal field theory,” Journal of Statistical Mechanics: Theory and Experiment, vol. 2018, no. 11, p. 113103, 2018.
- Harper, A. Mollabashi, T. Takayanagi, and Y. Taki, “Timelike entan-glement entropy,” Journal of High Energy Physics, vol. 2023, no. 5, pp. 1-62, 2023.
- W. Pang, “Holographic entanglement entropy of nonlocal field theories,” Physical Review D, vol. 89, no. 12, p. 126005, 2014.
- Anselmi, D. (2015). Quantum gravity and renormalization. Modern Physics Letters A, 30(03n04), 1540004. 10.1142/S0217732315400047.

Research & Reviews : Journal of Physics
| Volume | |
| Received | 22/10/2024 |
| Accepted | 26/12/2024 |
| Published | 07/02/2025 |