Saved in:
Bibliographic Details
Main Authors: Ho, Pei-Ming, Kawai, Hikaru, Liao, Henry
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.23443
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866918359075913728
author Ho, Pei-Ming
Kawai, Hikaru
Liao, Henry
author_facet Ho, Pei-Ming
Kawai, Hikaru
Liao, Henry
contents We consider actions that are general functions of the worldsheet/worldvolume metric and the induced metric for extended objects embedded in spacetime as Riemannian manifolds, areal-metric manifolds, and volume-metric manifolds. For strings on a Riemannian spacetime, we consider general actions respecting volume-preserving diffeomorphisms (VPD), general diffeomorphisms, and diffeomorphisms with Weyl symmetry, respectively. Well-known Schild, Nambu-Goto, and Polyakov actions are included as special cases. We reach two main conclusions: (1) When actions are functions of both the worldsheet metric and induced metrics, all nontrivial self-consistent actions are classically equivalent. (2) As a physical constraint on the classical action, VPD symmetry is as strong as the full diffeomorphism symmetry. The discussion is then extended to strings in spacetime manifolds equipped with the areal or volume metrics. Then, we further consider higher-dimensional extended objects in spacetime defined with areal or volume metrics, and show the equivalence between the generalized Schild actions and the generalized Nambu-Goto action. We prove a general theorem on VPD that explains this equivalence. Incidentally, while only the areal metric is needed to define the string worldsheet action, we show that the Polyakov action with an areal-metric perturbation cannot describe critical strings without other interaction terms.
format Preprint
id arxiv_https___arxiv_org_abs_2602_23443
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle General Actions of Extended Objects and Volume-Preserving Diffeomorphism
Ho, Pei-Ming
Kawai, Hikaru
Liao, Henry
High Energy Physics - Theory
We consider actions that are general functions of the worldsheet/worldvolume metric and the induced metric for extended objects embedded in spacetime as Riemannian manifolds, areal-metric manifolds, and volume-metric manifolds. For strings on a Riemannian spacetime, we consider general actions respecting volume-preserving diffeomorphisms (VPD), general diffeomorphisms, and diffeomorphisms with Weyl symmetry, respectively. Well-known Schild, Nambu-Goto, and Polyakov actions are included as special cases. We reach two main conclusions: (1) When actions are functions of both the worldsheet metric and induced metrics, all nontrivial self-consistent actions are classically equivalent. (2) As a physical constraint on the classical action, VPD symmetry is as strong as the full diffeomorphism symmetry. The discussion is then extended to strings in spacetime manifolds equipped with the areal or volume metrics. Then, we further consider higher-dimensional extended objects in spacetime defined with areal or volume metrics, and show the equivalence between the generalized Schild actions and the generalized Nambu-Goto action. We prove a general theorem on VPD that explains this equivalence. Incidentally, while only the areal metric is needed to define the string worldsheet action, we show that the Polyakov action with an areal-metric perturbation cannot describe critical strings without other interaction terms.
title General Actions of Extended Objects and Volume-Preserving Diffeomorphism
topic High Energy Physics - Theory
url https://arxiv.org/abs/2602.23443