{"id":"e6016add-400a-4eba-b453-0ebfe3080585","arxiv_id":"2606.03637","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":7.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":0,"one_line_summary":"Terahertz Faraday spectroscopy resolves opposite circular polarizations of long-lived CdGM resonances from electron- and hole-like bands in FeTe1-xSex, enabling band-resolved extraction of quasiparticle lifetimes, vortex masses, coherence lengths, and upper critical fields.","lead":"The paper uses terahertz Faraday magneto-optical spectroscopy on epitaxial FeTe1-xSex films to resolve the helicity of Caroli-de Gennes-Matricon vortex-core states, finding opposite circular polarizations for electron-like and hole-like bands. A smart generalist might read it to learn about a new optical method for probing multiband superconductivity and vortex dynamics without needing direct tunneling measurements.","discovery_kind":"new_method","skeptic_critique":{"model":"grok-4.3","headline":"No significant objection identified","rationale":"Reader's weakest assumption (correct band assignment via polarization selectivity without significant mixing or extraneous contributions) is the only plausible soft spot, but the given text supplies no evidence that this assumption fails. Full-text access does not reveal contradictions with the abstract-level claim, so the provisional UNVERDICTED verdict stands.","tokens_in":1698,"tokens_out":274,"duration_ms":13805,"concrete_test":"Re-analyze the raw Faraday rotation spectra (if available) by fitting with a two-component model that includes possible interband mixing terms; if the extracted opposite-helicity resonances remain statistically significant and their field and temperature dependence match the expected CdGM scaling, the assignment holds.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim is that polarization-selective THz Faraday spectroscopy cleanly resolves helical CdGM resonances from electron- versus hole-like bands, enabling band-resolved extraction of lifetimes, masses, coherence lengths and Hc2. The abstract states the method exploits polarization-selective optical transitions and reports opposite circular polarizations for the two band types. No internal inconsistency, hidden assumption in the selection rules, or unsupported step in the assignment is visible from the provided description. The approach is consistent with known magneto-optical selection rules for chiral vortex-core states in multiband systems.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","summary":"The manuscript reports the application of terahertz Faraday magneto-optical spectroscopy to epitaxial FeTe_{1-x}Se_x thin films to probe quantized helical Caroli-de Gennes-Matricon (CdGM) states in a nodeless multiband superconductor with short coherence lengths. By exploiting polarization-selective optical transitions, the authors resolve opposite circular polarizations for electron- and hole-like bands, enabling independent extraction of band-resolved quasiparticle lifetimes, vortex masses, coherence lengths, and upper critical fields, together with their evolution under isovalent substitution.","tokens_in":1790,"tokens_out":352,"duration_ms":16295,"significance":"If the band assignments and lifetime/mass extractions are robust, the work provides a new polarization-resolved spectroscopic route to helical vortex-core excitations and supplies dynamical evidence for multiband CdGM states in iron-based superconductors. The clean separation of electron- versus hole-like contributions via circular polarization is a clear methodological strength.","major_comments":[],"minor_comments":[{"comment":"The abstract states that the resonances are 'long-lived' and that lifetimes are extracted, but the main text should explicitly tabulate the extracted lifetimes (with uncertainties) alongside the corresponding polarization channels and magnetic-field values to allow direct assessment of the band-resolved claims.","section":"Results"},{"comment":"Figure captions and the methods section should state the precise fitting model (e.g., Lorentzian lineshape parameters, background subtraction) used to extract resonance positions and widths; without this, reproducibility of the reported coherence lengths and H_{c2} values is difficult to verify.","section":"Methods"}],"recommendation":"minor_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"We thank the referee for the positive summary, significance assessment, and recommendation of minor revision. No major comments were provided in the report.","responses":[],"tokens_in":1191,"tokens_out":46,"duration_ms":5016,"standing_objections":[]},"desk_editor":{"model":"grok-4.3","letter":"The central point is that terahertz Faraday magneto-optics with helicity resolution can separate long-lived CdGM resonances by band origin in these multiband films. The authors report opposite circular polarizations for electron-like versus hole-like bands and use that to pull out band-specific lifetimes, vortex masses, coherence lengths, and Hc2 values, plus their change with isovalent substitution.\n\nWhat is actually new is the polarization-selective optical probe itself. Prior CdGM work has been dominated by tunneling; this dynamical, bulk-sensitive approach gives access to relaxation times and mass parameters that STM does not directly yield. The method appears consistent with known magneto-optical selection rules for chiral vortex states.\n\nThe data presentation and analysis details are not visible in the abstract alone, so the strength of the band assignments rests on how cleanly the polarization selectivity works in practice. If other excitations or weak band mixing contribute at the same frequencies, the separation could be less clean than claimed, but nothing in the described logic flags an internal contradiction.\n\nThis is useful for the iron-based superconductor and vortex-core community. Readers who care about multiband quasiparticle dynamics or need an optical complement to STM will get concrete numbers and trends they can compare against theory. It is not a broad-theory paper.\n\nI would send it to peer review. The experimental claim is specific enough to be checked and the technique is worth documenting even if later work refines the assignments.","headline":"The paper shows a workable THz Faraday route to helicity- and band-resolved CdGM spectroscopy in FeTeSe, with opposite circular polarizations for electron and hole bands.","tokens_in":2347,"tokens_out":369,"would_cite":false,"duration_ms":13445,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.3","headline":"Terahertz Faraday spectroscopy resolves opposite circular polarizations of CdGM states from electron- and hole-like bands in multiband iron superconductors.","keywords":["Caroli-de Gennes-Matricon states","terahertz spectroscopy","FeTe1-xSex","vortex cores","multiband superconductivity","Faraday rotation","chirality","quasiparticle lifetime"],"falsifier":"A measurement in which the resonances do not exhibit opposite circular polarizations or fail to show the expected magnetic-field dependence for CdGM states would falsify the band-resolved assignment.","tokens_in":2610,"feed_emoji":"🌀","tokens_out":693,"duration_ms":15416,"temperature":0.7,"pith_summary":"The paper applies terahertz Faraday magneto-optical spectroscopy to epitaxial thin films of FeTe1-xSex to study quantized helical Caroli-de Gennes-Matricon states inside superconducting vortices. Polarization-selective transitions allow distinction of resonances from electron-like and hole-like bands by their opposite circular polarizations. This separation yields independent values for quasiparticle lifetimes, vortex masses, coherence lengths, and upper critical fields for each band type. The measurements track how these quantities change with selenium substitution for tellurium. A reader would care because it offers a direct optical way to disentangle contributions from different bands in a complex superconductor.","feed_headline":"Polarization separates electron and hole vortex states in FeTeSe","feed_subtitle":"Terahertz Faraday spectroscopy measures band-specific lifetimes and lengths, tracking changes with selenium content.","key_machinery":"Polarization-selective optical transitions that separate helical CdGM resonances by circular polarization according to their electron or hole band origin","core_discovery":"By exploiting polarization-selective optical transitions in terahertz Faraday magneto-optical spectroscopy, the authors directly resolve the helicity and band origin of vortex-core quasiparticles in FeTe1-xSex. They observe long-lived CdGM resonances with opposite circular polarizations for electron- and hole-like bands. This enables independent, band-resolved determination of quasiparticle lifetimes, vortex masses, coherence lengths, and upper critical fields, revealing their systematic evolution with isovalent substitution. The results establish terahertz magneto-optics as a direct probe of helical vortex-core excitations and provide dynamical evidence for multiband CdGM states in iron-bas","pith_inferences":["The method could apply to other multiband superconductors to separate band contributions that conventional probes mix together.","Band-specific coherence lengths might be compared against predictions from different pairing symmetries in iron-based materials.","Long-lived resonances open the possibility of using vortex-core states for time-resolved studies of quasiparticle dynamics."],"forward_implications":["Quasiparticle lifetimes can be measured separately for electron-like and hole-like bands.","Vortex masses, coherence lengths, and upper critical fields become accessible on a per-band basis.","These parameters evolve systematically with isovalent selenium substitution.","Terahertz magneto-optics provides dynamical evidence for multiband CdGM states."],"fun_headline_variants":["Chirality resolved CdGM states in FeTeSe by terahertz spectroscopy","Opposite polarizations identify electron and hole vortex states in FeTeSe","Band specific vortex quasiparticle lifetimes in FeTeSe","Terahertz Faraday spectroscopy resolves CdGM helicity in FeTeSe","Band resolved helical CdGM states probed in multiband FeTeSe"],"cache_read_input_tokens":64,"weakest_assumption_plain":"The observed terahertz resonances are correctly assigned to helical CdGM states originating from specific electron- versus hole-like bands, with polarization selectivity providing clean separation without significant contributions from other excitations or band mixing.","fun_headline_variants_meta":{"raw":{"variants":["Chirality resolved CdGM states in FeTeSe by terahertz spectroscopy","Opposite polarizations identify electron and hole vortex states in FeTeSe","Band specific vortex quasiparticle lifetimes in FeTeSe","Terahertz Faraday spectroscopy resolves CdGM helicity in FeTeSe","Band resolved helical CdGM states probed in multiband FeTeSe"]},"model":"grok-4.3","cost_usd":0.008376,"raw_usage":{"total_tokens":3784,"prompt_tokens":652,"num_sources_used":0,"completion_tokens":81,"cost_in_usd_ticks":83762000,"prompt_tokens_details":{"text_tokens":652,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":3051,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":652,"tokens_out":81,"duration_ms":17527,"temperature":1.0,"reasoning_tokens":3051,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-06-28T08:02:51.995973+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"A measurement in which the resonances do not exhibit opposite circular polarizations or fail to show the expected magnetic-field dependence for CdGM states would falsify the band-resolved assignment.","supporting_citations":[],"review_version":1}