Quasiparticle Collapse, Dark Energy Phase Transition, and the Spacetime Ladder Theory: A Unified Interpretation of Amplified Entanglement in Quantum Critical Metals
The recent experimental observation of amplified multipartite entanglement at the Kondo destruction quantum critical point (QCP) in strange metals, as quantified by the quantum Fisher information (QFI), presents a profound challenge to the conventional Landau quasiparticle framework. In this paper, we interpret this landmark result—reported by Fang et al. (Nature Communications, 2025) and extended by Kirschbaum et al. (Nature Physics, 2026)—through the lens of the Spacetime Ladder Theory (STLT). We propose that quasiparticle collapse is not mere loss of coherence but a macroscopic phase transition: matter (the contracted phase of dark matter) de-polarizes under an increasing qi-induction field strength Q, passes through a dark-matter intermediate state, and re-polarizes as dark energy (the expanded phase). This three-phase analogy—dark matter as water, matter as ice, dark energy as steam—provides an intuitive yet quantitatively consistent framework. The QFI peak at the QCP corresponds to maximal entropy production during the phase transition, and the emergent Weyl–Kondo semimetal dome in CeRu4Sn6 maps onto a region of coexisting phases stabilized by quantum critical fluctuations. We further argue that the STLT unifies laboratory-scale (10−9 m) quantum phenomena with cosmological-scale (1020 m) observations including the Hubble tension and galactic rotation curves, through a single dynamical equation F = m(E + v × Q). Testable predictions are proposed.
The recent experimental observation of amplified multipartite entanglement at the Kondo destruction quantum critical point (QCP) in strange metals, as quantified by the quantum Fisher information (QFI), presents a profound challenge to the conventional Landau quasiparticle framework. In this paper, we interpret this landmark result—reported by Fang et al. (Nature Communications, 2025) and extended by Kirschbaum et al. (Nature Physics, 2026)—through the lens of the Spacetime Ladder Theory (STLT). We propose that quasiparticle collapse is not mere loss of coherence but a macroscopic phase transition: matter (the contracted phase of dark matter) de-polarizes under an increasing qi-induction field strength Q, passes through a dark-matter intermediate state, and re-polarizes as dark energy (the expanded phase). This three-phase analogy—dark matter as water, matter as ice, dark energy as steam—provides an intuitive yet quantitatively consistent framework. The QFI peak at the QCP corresponds to maximal entropy production during the phase transition, and the emergent Weyl–Kondo semimetal dome in CeRu4Sn6 maps onto a region of coexisting phases stabilized by quantum critical fluctuations. We further argue that the STLT unifies laboratory-scale (10−9 m) quantum phenomena with cosmological-scale (1020 m) observations including the Hubble tension and galactic rotation curves, through a single dynamical equation F = m(E + v × Q). Testable predictions are proposed.
Strong correlations in matter promote a landscape of quantum phases and associated quantum critical points. For metallic systems, there is increasing recognition that the quantum criticality goes beyond the Landau framework and, thus, further means are needed to characterize the quantum critical fluid. Here we do so by studying an entanglement quantity, the quantum Fisher information, in a strange metal system, focusing on the exemplary case of an Anderson/Kondo lattice model near its Kondo destruction quantum critical point. The spin quantum Fisher information peaks at the quantum critical point and indicates a strongly entangled ground state. Our results are supported by the quantum Fisher information extracted from inelastic neutron scattering measurements in heavy fermion metals. Our work elucidates the loss of quasiparticles in strange metals, opens a quantum information avenue to advance the understanding of metallic quantum criticality in a broad range of strongly correlated systems, and points to a regime of quantum matter to realize amplified entanglement. Strange metals exhibit anomalous electronic and thermodynamic properties near a quantum critical point. Here the authors show theoretically that entanglement quantified by quantum Fisher information is amplified in a strange metal at a quantum critical point, which is supported by analysis of experimental data.
Strange metals exemplify highly collective quantum many-body systems that call for new means of characterization, and there is considerable potential for quantum information approaches contributing to the cause. We investigate multipartite entanglement across the quantum phase transition of a Kondo lattice model using the quantum Fisher information (QFI). We show that the QFI associated with the spin components transverse to the order parameter characterizes the destruction of heavy quasiparticles in the Kondo-destroyed magnetic-ordered phase. The physical origin of this observation is elucidated through an analysis of the antiferromagnetic Heisenberg model. We propose to test the results in terms of both unpolarized and polarized inelastic neutron scattering measurements in the ordered part of the heavy fermion phase diagram. Our findings illustrate how different operators of a many-body system can be employed to not only witness multipartite entanglement in different sectors and but also elucidate the overall physics across different parts of the phase diagram.
We present the Dynamical Scalar Field Theory (DSFT), a complete and self- consistent framework that explains quantum entanglement as a topological remnant of the pre-Big Bang Euclidean phase. In this theory, entanglement is not a nonlocal correlation but a geometric property of spacetime: two entangled particles are connected by a static topological soliton (phase-locking filament) within which the effective metric becomes Euclidean (Ω = 0, dt = 0), rendering spatial separation meaningless. We derive the full Lagrangian from first principles, including non-minimal cou- pling to matter (ξϕ2ρm) and curvature (αϕ2R), and demonstrate the existence of stable soliton solutions via the Bogomol’nyi bound. The decoherence process is identified as a sudden geometric phase transition (Ω : 0 → 1) occurring on the Planck time scale (∼ 10−43 s), independent of spatial distance. A detailed numerical analysis resolves previous dimensional inconsistencies: the correct prediction for the soliton response time is τresp ≈ 5.4 × 10−42 s, not 85 as. The attosecond time scale can be recovered only by introducing a perturbative term γϕ˙2ϕ 2 with γ ∼ 1050, which acts as a dynamical slowing mechanism. We further derive a dynamic cancellation mechanism via α(ϕ) that maintains soliton stability across a wide range of matter densities. Our model predicts FQ ∼ 1049 for a macroscopic crystal at T ∼ 10 K, in quantitative agreement with the recent Nature Physics observation of multipartite entanglement in the strange metal CePdSi (Mazza et al., 2026). The framework offers seven distinct predictions, five of which are experimentally testable with current or near-future technology. This work establishes DSFT as a mathematically rigorous, falsifiable theory that bridges quantum information, condensed matter, and gravitational physics, providing a physical mechanism for entanglement without violating causality or Lorentz invariance. https://doi.org/10.5281/zenodo.20724433 New version of this DOI
Standard quantum mechanics separates unitary time evolution from non-unitary measurement collapse, creating a severe foundational bottleneck when applied to closed cosmological systems where no external classical observer exists to collapse primordial quantum fluctuations. Simultaneously, modern cosmology faces unexplained dark-sector anomalies, including dark energy, dark matter, and Hubble/structure growth tensions. In this paper, we establish the Dynamical Quantum Measurement and Cosmological Quantum-to-Classical Transition (DQMCQT) framework, unifying and upgrading items #6 (Dynamical Foundations of Quantum Measurement), #5 (Early Universe and Quantum-to-Classical Transition), and #4 (Dark Sector and Cosmological Effective Laws) of the 20 Emergent Physics Agenda. Anchored in our 71-page ZFC Master Monograph (Lee, 2026, DOI: 10.5281/zenodo.23486681) and synthesized with the SVKES and HDGPS frameworks, we formulate coupled system–apparatus–gravity evolution on the Takesaki Type II₁ factor (ℳ_ground, τ_ground) with τ_ground(1_ℳ) = 1, governed by the URRHC idempotent modal reflection monad T_URRHC (T_URRHC² = T_URRHC) and universal constants 𝔘 = (𝒯_0x8A2C, C_UPTC, η_friction, ε_SHID). We establish six core axioms (DQMCQT-1 through DQMCQT-6) and prove six fundamental theorems: (1) Objective Pointer-State Contraction ‖ρ̂_t − T_URRHC(ρ̂_t)‖_tr ≤ η_friction in finite Lambert W₀ time τ_freeze = −(C_UPTC / Γ_dec) W₀(−Γ_dec η_friction / C_UPTC) < ∞ without ad-hoc collapse postulates, recovering the exact Born rule p_k = τ_ground(ρ̂_t Π̂_k); (2) Quantitative Visibility Deviation ΔV(t) = V_QM(t) − V_DQMCQT(t) > 0 from standard linear Lindblad decoherence when entanglement information crosses I_ent > ε_SHID, testable in macroscopic matter-wave interferometry; (3) Primordial Quantum-to-Classical Freezing of Mukhanov–Sasaki curvature perturbations R̂_k at Hubble horizon exit (2N_freeze ≥ C_UPTC) with oscillatory power spectrum cutoff; (4) Unified Dark-Sector Effective Action S_dark[g, φ_dec] where kinetic transition condensates and potential floors simultaneously yield the cosmic dark-to-baryonic matter ratio Ω_DM,0 / Ω_b,0 = C_UPTC / (12 c_𝒯 (1 + ε_SHID)) ≈ 5.33 and a thawing dynamic dark-energy equation of state w_eff(z) = −1 + (ε_SHID² / (3 C_UPTC)) (1 + z)^(c_𝒯 / (1 + c_𝒯)) > −1; (5) Primordial Quantum Discord and Scale-Dependent Non-Gaussian Bispectrum Bounds |f_NL^trans(k)| ≤ (5/12) ε_SHID c_𝒯 < 1; and (6) Anytime-Valid Martingale e-Value Model Selection (E_N ≥ 1/α) separating Unified Dark Physics from ΛCDM. Complete Python numerical verification is provided in Appendix A.
Quantum Fisher information (QFI) is a measure of multipartite quantum entanglement that can be obtained from inelastic neutron scattering data on quantum magnets. In this work, we demonstrate that the QFI can distinguish an unconventional quantum critical point (QCP) with fractionalization and emergent gauge structure from conventional ones within the Landau paradigm. We compute the QFI, via large-scale quantum Monte Carlo (QMC) simulations and exact diagonalization, in a kagome lattice quantum spin liquid (QSL) model with an XY and a cluster-Ising interactions. When the XY interaction is ferromagetic, the QFI obtained by QMC reveals a large anomalous dimension, which is a fingerprint of the (2+1)d XY∗ universality class for the transition from the ferromagnetic phase to the Z2 QSL. The investigation of thermal and dynamical properties of QFI is further extended to the case of antiferromagnetic XY interaction via exact diagonalization. In this regime, a transition to a possibly distinct QSL phase is suggested via both entanglement-based probes, such as QFI and genuine multipartite negativity, and analyses of the energy spectrum and structure factors. These results not only demonstrate the versatility of QFI in identifying QSL states and unconventional QCPs but also provide useful guidance for future theoretical and experimental studies of frustrated magnets.
We study the impurity entanglement entropy Se in quantum impurity models that feature a Kondo-destruction quantum critical point (QCP) arising from a pseudogap in the conduction-band density of states or from coupling to a bosonic bath. On the local-moment (Kondo-destroyed) side of the QCP, the entanglement entropy contains a critical component that can be related to the order parameter characterizing the quantum phase transition. In Kondo models describing a spin-$\Simp$, Se assumes its maximal value of $\ln(2\Simp+1)$ at the QCP and throughout the Kondo phase, independent of features such as particle-hole symmetry and under- or over-screening. In Anderson models, Se is nonuniversal at the QCP, and at particle-hole symmetry, rises monotonically on passage from the local-moment phase to the Kondo phase; breaking this symmetry can lead to a cusp peak in Se due to a divergent charge susceptibility at the QCP. Implications of these results for quantum critical systems and quantum dots are discussed.