{"id":"f80acd26-7cb6-4972-80b8-47d0fc5771a1","arxiv_id":"2607.24936","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":5,"one_line_summary":"In the t-t'-J model, electron doping (t'>0) selectively enhances coherent quasiparticle weight at antinodes while nodal weight stays resonance-driven and incoherent, yielding a momentum-split two-fluid spectrum.","lead":"The paper argues that electron-doped cuprates host two kinds of low-energy carriers split by momentum: conventional quasiparticles at the antinodes and strongly correlated composite modes at the nodes. If right, it offers a single strong-coupling story for why electron- and hole-doped cuprates look so different yet share many non-Fermi-liquid traits.","discovery_kind":"extension","skeptic_critique":{"model":"moonshotai/kimi-k3","headline":"The controlled VMC core is solid, but the finite-doping \"explanation\" of electron-doped ARPES is delivered by a two-fluid Green's function whose sector partition (n_c̃=δ/2), vertex λ, and per-doping AFM folding schedule J_cp are uncontrolled fits — the agreement with experiment is partly built in, a","rationale":"The reader's weakest_assumption is the correct load-bearing point, and the CONDITIONAL verdict already encodes exactly the right split: accept the few-hole sign(t') asymmetry mechanism as a controlled contribution; do not treat the two-fluid Green's function as predictive until the sector weights are determined by a controlled finite-doping calculation. My stress-test sharpens this in three ways. First, the concern is not merely that parameters are free — it is that the VMC data themselves do not support the paper's asserted doping-dependent partition (C(k)≈0.22 at t'=0.25t implies resonance dominance persists in the few-hole limit, so the claim that \"c primarily dominates\" at low finite doping is an uncontrolled extrapolation). Second, the per-doping schedule J_cp = 0.4J → 0.25J → 0 across Fig. 8(a)–(c) means each panel is separately tuned, further weakening the \"explains the experimental evolution\" framing; with ~3 knobs per panel, qualitative consistency is close to guaranteed. Third, the admitted non-sum-rule superposition in Eq. (36) plus the shared vertex λ between the qp and com channels (Eqs. 30, 33) means the decomposition has unquantified cross-term and double-counting errors that should be bounded. Credit where due: the few-hole core has real independent support (DMRG agreement on energies, Z_k peak positions at (π,0)/(0,π) for t'>0 and (±π/2,±π/2) for t'<0, Bloch-ansatz control, t'=0 dispersion matching GFMC), and the authors are transparent about the phenomenological status of Sec. IV — this is honest illustration, not hidden fitting. Hence UNCHANGED rather than REJECT: the paper does not overclaim formal verification, and the requested remedy (controlled finite-doping determination of n_c/n_c̃) is precisely the reader's condition. The concrete test proposed — a refit-free comparison against cylinder DMRG residues — is feasible with existing methods and would settle whether the phenomenology tracks a real mechanism or merely decorates it.","tokens_in":40525,"tokens_out":2472,"duration_ms":81116,"concrete_test":"Two-step check. (a) Parameter sensitivity: recompute Fig. 8(b) at δ=0.14 with n_c̃ swept over {δ/4, δ/2, 3δ/4} while holding λ and J_cp fixed at the published values, and quantify the sum-rule violation ∫dωA_e(k,ω) vs. the exact value for Eq. (36). If the nodal-vs-antinodal weight balance or pocket structure changes qualitatively, the doping-evolution claim is parameter-driven. (b) Controlled anchor: run DMRG on a width-4–6 cylinder at small finite doping (δ=1/16, t'=+0.25t, same t/J=2) and extract the momentum-resolved quasiparticle residue Z_k and single-particle gap structure; compare the nodal/antinodal weight ratio to the two-fluid prediction with n_c fixed by the measured residues and λ, J_cp NOT refit. Agreement without refitting would convert the phenomenology into a prediction; systematic mismatch would show the partition/vertex must be derived, not chosen.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The paper's controlled content (Sec. III, single-/two-hole VMC with DMRG benchmarks on 8×8, Appendix E) genuinely establishes the sign-of-t' mechanism: at t'>0 beyond a level-crossing threshold the bare-quasiparticle kinetic channel activates selectively in the antinodal region. I find no load-bearing flaw there, though the sharp threshold t'/t=0.09 is extracted on a 12×12 OBC cluster whose kinetic-energy curves (Fig. 3) show \"abrupt jumps... from level crossings,\" so its precise value is plausibly finite-size-dependent — a secondary concern, not the central one. The load-bearing weakness is exactly where the reader put it: Sec. IV B. The strongest claim says the two-fluid Green's function \"accounts for the experimental electron-doped spectral evolution,\" but the construction of Fig. 8 rests on: (i) n_c̃=δ/2, which the authors themselves say is \"merely a convenient choice and does not carry intrinsic physical significance\"; (ii) λ set by hand (0.06J, 0.1J); (iii) J_cp scheduled per doping panel (0.4J → 0.25J → 0 at δ=0.06, 0.14, 0.20); and (iv) Eq. (36), a linear superposition that the text concedes does not preserve the local spectral-weight sum rule. With three tunable knobs per panel, reproducing three qualitative ARPES features (antinodal pockets at low δ, nodal pockets at intermediate δ, large FS at high δ) is weak evidence for the mechanism rather than a prediction of it. Worse, the claimed doping dependence of the partition (\"near the low-doping limit, c primarily dominates\") is asserted from an analytical plausibility argument, not from the VMC: the single-hole data show C(k)∼0.22 in the antinodal region even at t'=0.25t, i.e., resonance still supplies the majority of the kinetic energy, so the VMC does not fix which sector should dominate at any finite δ. If the true partition at low doping is ˜c-dominated, the low-doping antinodal-pocket picture (Fig. 8a) would need reweighting and the narrative of the doping evolution could change qualitatively. The cross","agreement_with_reader":"agree"},"referee_report":{"model":"moonshotai/kimi-k3","summary":"The manuscript addresses the electron–hole asymmetry of cuprate single-particle spectra within the single-band t-t′-J model, using the phase-string representation. The controlled part of the work is a variational Monte Carlo (VMC) study of the single- and two-hole-doped model: the single-hole ground state is decomposed into a bare-quasiparticle component and an incoherent (twisted-hole) component, and the kinetic energy is split accordingly (Eqs. 15–17). For t′<0 the kinetic energy is dominated by inter-component resonance concentrated in the nodal region; for t′>0 beyond a threshold t′/t≈0.09 an intrinsic quasiparticle propagation channel activates selectively in the antinodal region (Figs. 3–4). The ansatz is benchmarked against DMRG on 8×8 clusters (App. E, Table II, Fig. ES12). Building on this, the authors propose a two-fluid ground state |Ψ_c⟩⊗|Ψ_G⟩ for t′>0 (Eq. 21b) and construct a phenomenological finite-doping Green's function — an RPA recombination channel (Eq. 30) plus a coherent channel (Eq. 33), with static AFM folding (Eq. 34) and a linear superposition (Eq. 36) — whose zero-energy spectra (Fig. 8) reproduce the experimental sequence: antinodal pockets at low doping, nodal pockets at intermediate doping, and a large Fermi surface at high doping.","tokens_in":41073,"tokens_out":2785,"duration_ms":70846,"significance":"If the controlled part holds, the paper identifies a concrete, physically transparent mechanism for the electron–hole asymmetry of the t-t′-J model: the sign of t′ controls whether the bare-quasiparticle hopping channel contributes constructively to the kinetic energy, and this contribution is momentum-selective (antinodal for t′>0). Strengths that deserve explicit credit: (i) the single-hole VMC ansatz is benchmarked against DMRG for both energies and the momentum-resolved quasiparticle weight Z_k (App. E), and the t′=0 dispersion is checked against Green-function Monte Carlo; (ii) the kinetic-energy decomposition in Eqs. (16)–(17) is a well-defined, ansatz-internal diagnostic, and the ratio C(k) in Fig. 4 provides a falsifiable momentum-resolved measure that other numerical methods (DMRG, DQMC) could test; (iii) the Bloch-wave control calculation (Sec. III C) cleanly demonstrates that the antinodal mode at t′>0 is conventional in character while the nodal mode at t′<0 is not. The finite-doping Green's function, by contrast, is explicitly phenomenological and its agreement with ARPES is at best illustrative; the paper is best read as a controlled single-/two-hole study plus a moti","major_comments":[{"comment":"The central finite-doping claim — that the two-fluid Green's function 'accounts for' the experimental electron-doped spectral evolution — is load-bearing for the paper's second stated question (b), but the construction has at least three free knobs per panel: the sector partition n_c̃=δ/2 (which the text itself describes as 'merely a convenient choice and does not carry intrinsic physical significance'), the recombination vertex λ (0.1J in Fig. 8, but 0.06J in the otherwise analogous hole-doped Fig. 7), and a per-doping AFM folding schedule J_cp = 0.4J, 0.25J, 0 at δ = 0.06, 0.14, 0.20. With three adjustable parameters per panel, reproducing three qualitative features (antinodal pockets, nodal pockets, large FS) is weak evidence for the mechanism rather than a prediction. The authors should either (a) provide a sensitivity analysis showing the qualitative sequence is robust over a substa","section":"Sec. IV B, Fig. 8, Eq. (36)"},{"comment":"The text concedes that the linear superposition G^e = G^{e,qp}_fold + G^{e,com}_fold 'does not strictly preserve the local sum rule for total spectral weight.' This is not a cosmetic issue: the spectral-weight sum rule is one of the few exact constraints available at finite doping, and a Green's function that violates it can manufacture apparent pocket weight or Fermi-surface area that has no physical meaning. The authors should quantify the violation (e.g., report the integrated weight ∫dω A^e(k,ω) versus the exact value for representative k points or as a k-average), and/or construct the superposition with explicit weight factors w_qp(k), w_com(k) chosen to restore the sum rule, showing that the qualitative features of Fig. 8 survive.","section":"Sec. IV B.2, Eq. (36)"},{"comment":"The threshold t′/t = 0.09 for the activation of the coherent antinodal channel is quoted as a sharp number in the abstract-level claims and the Conclusion, but Fig. 3 shows that the kinetic-energy curves exhibit 'abrupt jumps... from level crossings' on a 12×12 open-boundary cluster. Level crossings on a finite OBC cluster are generically size-dependent, so the threshold value (and possibly its sharpness) may be a finite-size artifact. Since the two-fluid picture of Sec. IV is premised on this channel being active at physical t′/t ≈ 0.2–0.3, the authors should either demonstrate size convergence of the threshold (e.g., 8×8 vs 12×12 vs 16×16, or twisted boundary conditions to move the crossing points) or state clearly that 0.09 is an estimate whose precise value is not controlled. This is a bounded, feasible addition within the existing VMC machinery.","section":"Sec. III A, Fig. 3; Conclusion"},{"comment":"The factorized form |Ψ_{t′>0}⟩ = |Ψ_c⟩ ⊗ |Ψ_G⟩ is presented as the synthesis of the VMC results, but the VMC calculations are performed at the single- and two-hole level, where '⊗' has no operative meaning — there is no density of coherent carriers to factorize. Eq. (21b) is therefore an ansatz extrapolated to finite doping, not a result of Sec. III. This matters because the entire two-fluid counting (δ = n_c + n_c̃) and the independent-mode language of Sec. IV B rest on it. The authors should state explicitly that Eq. (21b) is a hypothesis motivated by the single-hole diagnostics, and ideally provide at least one finite-doping consistency check (e.g., a two-hole or few-hole calculation showing additive behavior of E_K^qp, or a VMC energy comparison of the factorized form against an unfactorized ansatz at small finite δ).","section":"Sec. III C, Eq. (21b)"}],"minor_comments":[{"comment":"Typo: 'open boundary conditionss' (extra s). Also Eq. (25) ends with a stray comma.","section":"Sec. II A"},{"comment":"λ = 0.06J is used for the hole-doped Fermi arc (Fig. 7) but λ = 0.1J for all electron-doped panels (Fig. 8). If this difference is physically motivated (e.g., doping- or sign-dependence of the recombination vertex), it should be stated; otherwise a common value would make the comparison cleaner.","section":"Sec. IV A vs IV B"},{"comment":"The axis labels are missing from the reproduced figure; please ensure the published version labels the ordinate (energies in units of J?) and identifies the three curves with a legend rather than only in the caption.","section":"Fig. 3"},{"comment":"The state-selection rule for C(k) ('the eigenstate whose energy lies closest to ω(k) and carries the largest spectral weight') is ambiguous when these two criteria select different states; please specify the tie-breaking procedure.","section":"Sec. III B"},{"comment":"The pink/blue color coding distinguishing quasiparticle from composite weight is defined only in the caption; a legend or an explicit statement of how the two contributions are separated when plotting −Im(G_qp + G_com) (which is not additive in the spectral function after folding) would help the reader.","section":"Fig. 8"},{"comment":"The comparison with the DQMC study of Ref. [37] (momentum-dependent damping as the origin of the dichotomy) is mentioned but not engaged quantitatively; a sentence on whether the two pictures are complementary or competing would strengthen the discussion. Also, Ref. [37] and Ref. [39] are arXiv preprints; please update if published.","section":"Sec. I / Sec. V A"}],"recommendation":"major_revision","confidential_remarks":"The phase-string framework, the RPA recombination Green's function (Sec. IV A), and the mean-field inputs (App. B, Table I) are largely carried over from the authors' prior publications (Refs. [43–45, 53, 54, 78]); the genuinely new content is the Sec. III VMC study and the two-fluid proposal of Sec. IV B. This is disclosed in the text and is not a problem per se, but the editor may wish to weigh that the paper's controlled novel result is the single-/two-hole mechanism, while the experiment-facing part is a parametrized illustration. I do not see a correctness error in the controlled part; my major-revision recommendation reflects the gap between the strength of the finite-doping claims and the tunability of the construction supporting them, which I believe can be substantially closed within the scope of the present manuscript (sensitivity analysis, sum-rule quantification, finite-size check of the threshold)."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"The real payload is Sec. III. On 12×12 OBC they decompose the single-hole kinetic energy into bare-QP, incoherent, and cross (resonance) pieces and show that for t'<0 the resonance channel dominates and sits at the nodes, while for t'>0 past a level-crossing near 0.09t the bare-QP channel turns on selectively at the antinodes (C(k)∼0.22). Two-hole pairing stays tight d-wave + NNN incoherent for both signs, but positive t' lets the Cooper-pair piece hop on NNN bonds. DMRG on 8×8 checks energies and Z_k. That is new, inspectable, and cleanly extends the phase-string program.\n\nWhat they do well is keep the few-hole math honest: the twisted-hole ansatz, the orthogonal decomposition, the Bloch-wave control that fails for t'<0 and works for t'>0, and the sign-structure argument that positive t' interferes constructively with the AFM background. Citations are heavy on their own line, but the new VMC numbers are not just restatements.\n\nThe soft spot is exactly where the stress-test puts it, and it is load-bearing for the strongest claim. Sec. IV builds a two-fluid Green’s function (G^qp + G^com with AFM folding) whose sector weight n_˜c=δ/2, vertex λ, and J_cp schedule are free parameters chosen panel-by-panel to reproduce the experimental sequence (antinodal pockets → nodal pockets → large FS). The text itself calls n_˜c=δ/2 “merely a convenient choice” and notes that the linear sum does not preserve the local sum rule. Single-hole VMC still has resonance supplying most of the kinetic energy even at t'=0.25t, so it does not fix which fluid should dominate at finite δ. The agreement with ARPES is therefore illustrative, not predictive. Minor secondary issue: the quoted 0.09 threshold sits on finite-size level crossings.\n\nThis is for people already inside doped-Mott / phase-string or t-t'-J numerics who want a concrete mechanism for electron-hole spectral asymmetry. It deserves a serious referee; the few-hole core is real. I would engage the VMC part, cite the kinetic-energy split and the threshold observation, and treat the finite-doping GF as a motivated sketch until someone fixes the sector weights from a controlled calculation.","headline":"Solid single-/two-hole VMC shows sign(t') reweights kinetic energy into a momentum-selective coherent channel; the finite-doping ARPES story is a hand-tuned phenomenological GF, not a controlled prediction.","tokens_in":40975,"tokens_out":614,"would_cite":true,"duration_ms":13835,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.5","headline":"Electron-doped Mott insulators host momentum-separated coherent and incoherent excitations that explain their mixed Fermi-liquid and strong-correlation spectra.","keywords":["t-t'-J model","electron-doped cuprates","Mott insulator","phase string","quasiparticle","Fermi arc","antinodal dichotomy","variational Monte Carlo"],"falsifier":"A controlled finite-doping spectral calculation, or simultaneous high-resolution nodal and antinodal ARPES, showing that antinodal coherent weight and nodal composite weight do not remain distinct components whose relative weights evolve with the sign of t' as claimed, or that the single-hole kinetic-energy ratio fails to rise selectively at the antinodes above t'/t ≈ 0.09.","tokens_in":40370,"feed_emoji":"🧲","tokens_out":987,"duration_ms":40447,"temperature":0.7,"pith_summary":"Cuprate experiments show a sharp asymmetry: hole-doped materials form nodal Fermi arcs, while electron-doped ones first show antinodal electron pockets and only later develop nodal weight, yet both still display strong-correlation signatures. This paper claims that the t-t'-J model already contains the explanation. Its ground-state wave function always has two components—a coherent quasiparticle and an incoherent composite built from fractionalized pieces—and kinetic energy comes from both bare quasiparticle motion and resonance between the two. Variational Monte Carlo at the single-hole level shows that for hole doping (t'<0) the resonance dominates and sits at the nodes, whereas for electron doping (t'>0) the coherent channel is selectively enhanced at the antinodes while the nodes remain resonance-dominated. Extending that momentum-selective structure to finite doping with a two-fluid Green’s function reproduces the experimental spectral evolution and keeps both doping sides inside one doped-Mott framework.","feed_headline":"Electron doping splits cuprate excitations by momentum","feed_subtitle":"Coherent weight sits at antinodes; nodes stay strongly correlated, explaining mixed spectra.","key_machinery":"Two-component decomposition of the variational single-hole (and two-hole) wave function into orthogonal quasiparticle and incoherent pieces, rooted in the phase-string representation; kinetic energy is partitioned into bare quasiparticle hopping versus inter-component resonance, and a phenomenological two-fluid Green’s function carries the same separation to finite doping.","core_discovery":"The ground-state wave function of the t-t'-J model generically decomposes into a coherent quasiparticle component and an incoherent composite component. For t'<0 the low-energy kinetic energy is carried almost entirely by resonance between them and concentrates at the nodes. For t'>0 beyond a threshold, intrinsic quasiparticle propagation is selectively enhanced at the antinodes while the nodal region stays controlled by the incoherent composite, producing a momentum-space separation of the two components that accounts for the contrasting single-particle spectra of electron- and hole-doped cuprates.","pith_inferences":["If momentum locking of the two fluids only gradually softens with doping, intermediate-doping electron-doped samples should show hybrid damping rates that interpolate between Fermi-liquid and arc-like scattering.","Constructive NN–NNN interference for t'>0 that stabilizes antiferromagnetism predicts a slower collapse of the spin gap with doping than on the hole-doped side, testable by neutron or Raman spin-gap measurements.","Analogous two-component structures may appear in other doped Mott systems whenever next-nearest-neighbor hopping can partially bypass phase-string frustration."],"forward_implications":["Electron-doped spectra should retain a nodal–antinodal dichotomy in quasiparticle character even when long-range antiferromagnetism is absent.","The same incoherent composite sector produces both hole-doped Fermi arcs and the nodal weight that appears upon electron doping.","Superconducting Tc remains set by the spin-gap scale of the composite sector, so a larger local pair amplitude for t'>0 need not raise Tc.","Weaker non-Fermi-liquid transport on the electron-doped side follows from reduced weight of the composite component."],"fun_headline_variants":["Electron doping splits cuprate excitations by momentum","Coherent weight at antinodes, nodes stay incoherent in electron doping","t-t'-J wavefunction yields two components split by momentum","Antinodal quasiparticles selectively enhanced for electron doping","Momentum separates coherent and composite excitations in electron-doped Mott"],"cache_read_input_tokens":32896,"weakest_assumption_plain":"The jump from single- and two-hole cluster wave functions to finite doping is made with a phenomenological Green’s function whose component densities, recombination strength, and antiferromagnetic coupling are free parameters chosen to match spectra, not fixed by a controlled many-body calculation.","fun_headline_variants_meta":{"raw":{"variants":["Electron doping splits cuprate excitations by momentum","Coherent weight at antinodes, nodes stay incoherent in electron doping","t-t'-J wavefunction yields two components split by momentum","Antinodal quasiparticles selectively enhanced for electron doping","Momentum separates coherent and composite excitations in electron-doped Mott"]},"model":"grok-4.5","effort":"low","cost_usd":0.005391,"raw_usage":{"total_tokens":1565,"prompt_tokens":891,"num_sources_used":0,"completion_tokens":85,"cost_in_usd_ticks":53908000,"prompt_tokens_details":{"text_tokens":891,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":589,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":891,"tokens_out":85,"duration_ms":10665,"temperature":1.0,"reasoning_tokens":589,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-31T05:25:49.521579+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"A controlled finite-doping spectral calculation, or simultaneous high-resolution nodal and antinodal ARPES, showing that antinodal coherent weight and nodal composite weight do not remain distinct components whose relative weights evolve with the sign of t' as claimed, or that the single-hole kinetic-energy ratio fails to rise selectively at the antinodes above t'/t ≈ 0.09.","supporting_citations":[],"review_version":1}