{"work":{"id":"5c345b37-10c9-43b8-92ee-699af9ac7e62","openalex_id":null,"doi":null,"arxiv_id":"2603.10844","raw_key":null,"title":"Long-lived quasinormal modes, shadows and particle motion in four-dimensional quasi-topological gravity","authors":null,"authors_text":null,"year":2026,"venue":"gr-qc","abstract":"We investigate massive scalar perturbations and several characteristics of particle motion in the spacetime of regular black holes arising in four-dimensional quasi-topological gravity. Quasinormal modes are computed using high-order WKB approximations with Pad\\'e resummation and verified through time-domain integration. For moderate values of the scalar-field mass, the time-domain profiles confirm the WKB results with excellent accuracy. As the mass increases, the damping rate decreases substantially, indicating the approach to the quasi-resonant regime of long-lived modes. For sufficiently large masses, the late-time signal becomes dominated by oscillatory power-law tails, which mask the quasi-resonant mode in the time-domain profile. In addition, we analyze photon motion and circular geodesics, including the photon-sphere radius, shadow size, Lyapunov exponent, and ISCO characteristics. These quantities exhibit only moderate deviations from their Schwarzschild values, unlike the Hawking temperature of the black hole.","external_url":"https://arxiv.org/abs/2603.10844","cited_by_count":null,"metadata_source":"pith","metadata_fetched_at":"2026-06-30T00:04:06.268004+00:00","pith_arxiv_id":"2603.10844","created_at":"2026-05-11T10:26:00.061114+00:00","updated_at":"2026-06-30T00:04:06.268004+00:00","title_quality_ok":true,"display_title":"Long-lived quasinormal modes, shadows and particle motion in four-dimensional quasi-topological gravity","render_title":"Long-lived quasinormal modes, shadows and particle motion in four-dimensional quasi-topological gravity"},"hub":{"state":{"work_id":"5c345b37-10c9-43b8-92ee-699af9ac7e62","tier":"hub","tier_reason":"10+ Pith inbound or 1,000+ external citations","pith_inbound_count":10,"external_cited_by_count":null,"distinct_field_count":2,"first_pith_cited_at":"2026-03-06T19:00:00+00:00","last_pith_cited_at":"2026-05-19T22:29:19+00:00","author_build_status":"not_needed","summary_status":"needed","contexts_status":"needed","graph_status":"needed","ask_index_status":"not_needed","reader_status":"not_needed","recognition_status":"not_needed","updated_at":"2026-06-26T20:55:24.379615+00:00","tier_text":"hub"},"tier":"hub","role_counts":[{"context_role":"background","n":10}],"polarity_counts":[{"context_polarity":"background","n":10}],"runs":{},"summary":{},"graph":{},"authors":[]}}