Quantum models with the Yang-Lee phase transition
Pith reviewed 2026-06-26 16:41 UTC · model grok-4.3
The pith
Four 1+1D quantum models tuned by PT-symmetric deformations realize the Yang-Lee phase transition described by a massless boson with iφ³ interaction.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We present four different 1+1D quantum models that realize the Yang-Lee phase transition under a deformation that preserves PT symmetry. These are the antiferromagnetic Ising spin chain in transverse and longitudinal magnetic fields, the massive Schwinger model, the Blume-Capel model, and the three-state quantum clock model. Using the state-operator correspondence, we identify the YL critical point, compute the scaling dimensions of the lowest operators in each model, and find perfect agreement with the exact results for the YL criticality in two dimensions. Using bosonization for the Schwinger model and the Polyakov-Hubbard transformation for the other models, we show that in all of these q
What carries the argument
PT-symmetric deformations that tune the four models to the Yang-Lee fixed point, realized through state-operator correspondence and bosonization mappings to the massless bosonic field with i φ³ interaction.
If this is right
- Scaling dimensions of the lowest operators match exact Yang-Lee results in two dimensions.
- The two-point function of the field phi grows with distance at the critical point.
- In the quantum clock model the massless field couples to a massive bosonic field whose states appear in the Hamiltonian spectrum.
- All four microscopically distinct models flow to the same Yang-Lee universality class.
Where Pith is reading between the lines
- These lattice realizations may enable sign-problem-free numerical studies of the non-unitary Yang-Lee theory.
- Similar PT-symmetric deformations could be applied to other 1+1D models to reach additional non-Hermitian critical points.
- The consistency across spin chains, gauge theories, and clock models indicates that the i φ³ description is insensitive to microscopic details.
- Experimental systems with engineered PT symmetry could test signatures of the growing phi correlator.
Load-bearing premise
The chosen PT-symmetric deformations tune the models precisely to the Yang-Lee fixed point without additional relevant operators or lattice artifacts that would alter the universality class.
What would settle it
Numerical extraction of the scaling dimension of the lowest-lying operator in any of the four models that deviates from the known Yang-Lee value would falsify the claim that the models reach that critical point.
read the original abstract
In this article, we present four different $1+1$D quantum models that realize the Yang-Lee (YL) phase transition under a deformation that preserves $PT$ symmetry. These are the antiferromagnetic Ising spin chain in transverse and longitudinal magnetic fields, the massive Schwinger model, the Blume-Capel model, and the three-state quantum clock model. Using the state-operator correspondence, we identify the YL critical point, compute the scaling dimensions of the lowest operators in each model, and find perfect agreement with the exact results for the YL criticality in two dimensions. Using bosonization for the Schwinger model and the Polyakov-Hubbard transformation for the other models, we show that in all of these quantum models the YL critical point is described, as expected, by a massless bosonic field with an $i \phi^3$ interaction. In the quantum clock model, this critical field interacts with a massive bosonic field, and we identify the massless and massive states in the Hamiltonian spectrum. In addition, we numerically compute the two-point function of $\phi$ at the Yang-Lee critical point and show that it grows with distance, in agreement with theoretical expectations.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper constructs four 1+1D quantum models (antiferromagnetic Ising chain in transverse and longitudinal fields, massive Schwinger model, Blume-Capel model, and three-state quantum clock model) that realize the Yang-Lee edge singularity under PT-symmetric deformations. It identifies the critical points via state-operator correspondence, reports exact matching of the lowest scaling dimensions to the non-unitary YL CFT (c = -22/5), maps each critical theory to a massless boson with iφ³ interaction (via bosonization for the Schwinger model and Polyakov-Hubbard for the others), and numerically verifies that the two-point function of φ grows with distance.
Significance. If the central identifications hold, the work supplies concrete, numerically accessible lattice realizations of the non-unitary Yang-Lee CFT inside standard quantum spin and gauge models. The use of four independent models, the combination of state-operator correspondence with explicit field-theory mappings, and the direct numerical check of the growing correlator constitute clear strengths. These constructions open routes for studying non-unitary fixed points in condensed-matter and lattice-gauge settings without invoking complex couplings by hand.
minor comments (3)
- [Abstract] Abstract: the phrase 'perfect agreement' is stated without reference to a table or figure that lists the computed dimensions versus the exact YL values; adding such a compact comparison (even if already present in §4 or §5) would improve readability.
- The Polyakov-Hubbard mapping for the clock and Blume-Capel models is invoked without an explicit statement of the auxiliary-field decoupling or the resulting interaction terms; a short appendix deriving the iφ³ coefficient would strengthen the claim.
- Figure captions for the two-point function plots should explicitly state the system sizes, boundary conditions, and fitting procedure used to extract the growth, to allow independent verification of the numerical evidence.
Simulated Author's Rebuttal
We thank the referee for their positive assessment of the manuscript, the clear summary of its contributions, and the recommendation to accept. No major comments were raised.
Circularity Check
No significant circularity; derivation is self-contained via standard techniques
full rationale
The paper constructs PT-symmetric deformations of four known lattice models (Ising, Schwinger, Blume-Capel, clock) and identifies the YL critical point by computing scaling dimensions via state-operator correspondence, finding agreement with independently known 2D YL CFT values (c = -22/5 and operator dimensions). The iφ³ description follows from applying standard bosonization (Schwinger) and Polyakov-Hubbard (others) mappings, which are not derived from or fitted to the present numerics. The two-point function growth is a direct numerical check against theoretical expectations. No self-definitional steps, fitted inputs renamed as predictions, or load-bearing self-citations appear; all load-bearing steps are externally benchmarked or use established, non-circular mappings.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption State-operator correspondence of 2D conformal field theory applies directly to the deformed lattice models at the identified critical points
- domain assumption Bosonization and Polyakov-Hubbard transformations correctly map the microscopic models onto the massless boson plus iφ³ theory
Reference graph
Works this paper leans on
-
[1]
Kortman and R.B
P.J. Kortman and R.B. Griffiths,Density of Zeros on the Lee-Yang Circle for Two Ising Ferromagnets,Phys. Rev. Lett.27(1971) 1439
1971
-
[2]
Yang and T.D
C.-N. Yang and T.D. Lee,Statistical theory of equations of state and phase transitions. 1. Theory of condensation,Phys. Rev.87(1952) 404. – 42 –
1952
-
[3]
Lee and C.-N
T.D. Lee and C.-N. Yang,Statistical theory of equations of state and phase transitions. 2. Lattice gas and Ising model,Phys. Rev.87(1952) 410
1952
-
[4]
Fisher,Yang-Lee Edge Singularity andϕ 3 Field Theory,Phys.Rev.Lett.40(1978) 1610
M. Fisher,Yang-Lee Edge Singularity andϕ 3 Field Theory,Phys.Rev.Lett.40(1978) 1610
1978
-
[5]
Becker,Landau-Ginzburg theory, mean field and spin systems in imaginary magnetic fields, other thesis, 4, 1991
M. Becker,Landau-Ginzburg theory, mean field and spin systems in imaginary magnetic fields, other thesis, 4, 1991
1991
-
[6]
Becker,Generalized Ising model: Lee-Yang edge singularity, other thesis, 4, 1991
K. Becker,Generalized Ising model: Lee-Yang edge singularity, other thesis, 4, 1991
1991
-
[7]
von Gehlen,Critical and off critical conformal analysis of the Ising quantum chain in an imaginary field,J
G. von Gehlen,Critical and off critical conformal analysis of the Ising quantum chain in an imaginary field,J. Phys. A24(1991) 5371
1991
-
[8]
Gehlen,Non-Hermitian tricriticality in the Blume-Capel model with imaginary field, International Journal of Modern Physics B8(1994) 3507
G.V. Gehlen,Non-Hermitian tricriticality in the Blume-Capel model with imaginary field, International Journal of Modern Physics B8(1994) 3507
1994
-
[9]
L. Fei, S. Giombi and I.R. Klebanov,CriticalO(N)Models in6−ϵDimensions,Phys.Rev. D90(2014) 025018 [1404.1094]
Pith/arXiv arXiv 2014
-
[10]
L. Fei, S. Giombi, I.R. Klebanov and G. Tarnopolsky,Three loop analysis of the critical O(N) models in 6-εdimensions,Phys. Rev. D91(2015) 045011 [1411.1099]
Pith/arXiv arXiv 2015
-
[11]
Gracey,Four loop renormalization ofϕ 3 theory in six dimensions,Phys
J.A. Gracey,Four loop renormalization ofϕ 3 theory in six dimensions,Phys. Rev. D92 (2015) 025012 [1506.03357]
Pith/arXiv arXiv 2015
-
[12]
M. Borinsky, J.A. Gracey, M.V. Kompaniets and O. Schnetz,Five-loop renormalization ofϕ 3 theory with applications to the Lee-Yang edge singularity and percolation theory,Phys. Rev. D103(2021) 116024 [2103.16224]
arXiv 2021
-
[13]
M. Kompaniets and A. Pikelner,Critical exponents from five-loop scalar theory renormalization near six-dimensions,Phys. Lett. B817(2021) 136331 [2101.10018]
arXiv 2021
-
[14]
Schnetz,ϕ3 theory at six loops,Phys
O. Schnetz,ϕ3 theory at six loops,Phys. Rev. D112(2025) 016028 [2505.15485]
arXiv 2025
-
[15]
Gracey,Six loop critical exponent analysis for Lee-Yang and percolation theory,Phys
J.A. Gracey,Six loop critical exponent analysis for Lee-Yang and percolation theory,Phys. Rev. D112(2025) 105019 [2510.05723]
arXiv 2025
-
[16]
E. Arguello Cruz, I.R. Klebanov, G. Tarnopolsky and Y. Xin,Yang-Lee Quantum Criticality in Various Dimensions,Phys. Rev. X16(2026) 011022 [2505.06369]
arXiv 2026
-
[17]
W. Zhu, C. Han, E. Huffman, J.S. Hofmann and Y.-C. He,Uncovering Conformal Symmetry in the 3D Ising Transition: State-Operator Correspondence from a Quantum Fuzzy Sphere Regularization,Phys. Rev. X13(2023) 021009 [2210.13482]
arXiv 2023
-
[18]
Hu, Y.-C
L. Hu, Y.-C. He and W. Zhu,Operator Product Expansion Coefficients of the 3D Ising Criticality via Quantum Fuzzy Spheres,Phys. Rev. Lett.131(2023) 031601
2023
-
[19]
L. Hu, W. Zhu and Y.-C. He,Entropic F function of three-dimensional Ising conformal field theory via fuzzy sphere regularization,Phys. Rev. B111(2025) 155151 [2401.17362]
arXiv 2025
-
[20]
G. Fardelli, A.L. Fitzpatrick and E. Katz,Constructing the infrared conformal generators on the fuzzy sphere,SciPost Phys.18(2025) 086 [2409.02998]
arXiv 2025
-
[21]
A.M. L¨ auchli, L. Herviou, P.H. Wilhelm and S. Rychkov,Exact diagonalization, matrix product states and conformal perturbation theory study of a 3D Ising fuzzy sphere model, SciPost Phys.19(2025) 076 [2504.00842]
arXiv 2025
-
[22]
R. Fan, J. Dong and A. Vishwanath,Simulating the non-unitary Yang-Lee conformal field theory on the fuzzy sphere,2505.06342. – 43 –
-
[23]
J. Elias Mir´ o and O. Delouche,Flowing from the Ising model on the fuzzy sphere to the 3D Lee-Yang CFT,JHEP10(2025) 037 [2505.07655]
arXiv 2025
-
[24]
P. Butera and M. Pernici,Yang-Lee edge singularities from extended activity expansions of the dimer density for bipartite lattices of dimensionality 2<= d<= 7,Phys. Rev. E86 (2012) 011104 [1206.0872]
Pith/arXiv arXiv 2012
-
[25]
Cardy,Conformal Invariance and the Yang-lee Edge Singularity in Two-dimensions, Phys.Rev.Lett.54(1985) 1354
J.L. Cardy,Conformal Invariance and the Yang-lee Edge Singularity in Two-dimensions, Phys.Rev.Lett.54(1985) 1354
1985
-
[26]
Belavin, A.M
A.A. Belavin, A.M. Polyakov and A.B. Zamolodchikov,Infinite Conformal Symmetry in Two-Dimensional Quantum Field Theory,Nucl. Phys. B241(1984) 333
1984
-
[27]
P. Fonseca and A. Zamolodchikov,Ising field theory in a magnetic field: Analytic properties of the free energy,hep-th/0112167
-
[28]
Zamolodchikov,Conformal Symmetry and Multicritical Points in Two-Dimensional Quantum Field Theory.,Sov
A.B. Zamolodchikov,Conformal Symmetry and Multicritical Points in Two-Dimensional Quantum Field Theory.,Sov. J. Nucl. Phys.44(1986) 529
1986
-
[29]
A. Katsevich, I.R. Klebanov and Z. Sun,Ginzburg-Landau description of a class of non-unitary minimal models,JHEP03(2025) 170 [2410.11714]
arXiv 2025
-
[30]
A. Katsevich, I.R. Klebanov, Z. Sun and G. Tarnopolsky,Towards a Quintic Ginzburg-Landau Description of the (2,7) Minimal Model,Phys. Rev. Lett.136(2026) 111602 [2510.19085]
arXiv 2026
-
[31]
L. Zambelli and O. Zanusso,Lee-Yang model from the functional renormalization group, Phys. Rev. D95(2017) 085001 [1612.08739]
Pith/arXiv arXiv 2017
-
[32]
M. Lencs´ es, A. Miscioscia, G. Mussardo and G. Tak´ acs,Multicriticality in Yang-Lee edge singularity,2211.01123
-
[33]
M. Lencs´ es, A. Miscioscia, G. Mussardo and G. Tak´ acs,Ginzburg-Landau description for multicritical Yang-Lee models,JHEP08(2024) 224 [2404.06100]
arXiv 2024
-
[34]
D. Benedetti, F. Eustachon and O. Zanusso,Critical and multicritical Lee-Yang fixed points in the local potential approximation,2601.15087
-
[35]
Uzelac and R
K. Uzelac and R. Jullien,The Yang-Lee edge singularity by the phenomenological renormalisation group,Journal of Physics A: Mathematical and General14(1981) L151
1981
-
[36]
Itzykson, H
C. Itzykson, H. Saleur and J.-B. Zuber,Conformal Invariance of Nonunitary 2d-Models, Europhysics Letters2(1986) 91
1986
-
[37]
Novotny and D
M. Novotny and D. Landau,Zero temperature phase diagram for the d=1 quantum Ising antiferromagnet,Journal of Magnetism and Magnetic Materials54-57(1986) 685
1986
-
[38]
A. Ovchinnikov, D. Dmitriev, V.Y. Krivnov and V. Cheranovskii,The antiferromagnetic Ising chain in a mixed transverse and longitudinal magnetic field,arXiv preprint cond-mat/0306468(2003)
Pith/arXiv arXiv 2003
-
[39]
Schwinger,Gauge invariance and mass
J. Schwinger,Gauge invariance and mass. II,Phys. Rev.128(1962) 2425
1962
-
[40]
Lowenstein and J.A
J.H. Lowenstein and J.A. Swieca,Quantum electrodynamics in two dimensions.,Ann. Phys. (N. Y.) 68: No. 1, 172-95(Nov 1971).(1971)
1971
-
[41]
Casher, J
A. Casher, J. Kogut and L. Susskind,Vacuum polarization and the absence of free quarks, Phys. Rev. D10(1974) 732. – 44 –
1974
-
[42]
Gefen, Y
Y. Gefen, Y. Imry and D. Mukamel,Phase diagram of spin-1 quantum Ising models: Applications to systems of weakly coupled classical Ising chains,Phys. Rev. B23(1981) 6099
1981
-
[43]
Alcaraz, J.R
F.C. Alcaraz, J.R. Drugowich de Fel´ ıcio, R. K¨ oberle and J.F. Stilck,Hamiltonian studies of the Blume-Emery-Griffiths model,Phys. Rev. B32(1985) 7469
1985
-
[44]
Balbao and J.R.D
D.B. Balbao and J.R.D. de Felicio,Operator content of the Blume-Capel quantum chain, Journal of Physics A: Mathematical and General20(1987) L207
1987
-
[45]
D. Horn, M. Weinstein and S. Yankielowicz,Hamiltonian approach toZ(N)lattice gauge theories,Phys. Rev. D19(1979) 3715
1979
-
[46]
Ostlund,Incommensurate and commensurate phases in asymmetric clock models,Phys
S. Ostlund,Incommensurate and commensurate phases in asymmetric clock models,Phys. Rev. B24(1981) 398
1981
-
[47]
Huse,Simple three-state model with infinitely many phases,Phys
D.A. Huse,Simple three-state model with infinitely many phases,Phys. Rev. B24(1981) 5180
1981
-
[48]
V. Gorbenko and A. Zhabin,Chaos in Systems with Quantum Group Symmetry,2510.23247
-
[49]
Coleman,The Quantum Sine-Gordon Equation as the Massive Thirring Model,Phys
S.R. Coleman,The Quantum Sine-Gordon Equation as the Massive Thirring Model,Phys. Rev. D11(1975) 2088
1975
-
[50]
Coleman, R
S.R. Coleman, R. Jackiw and L. Susskind,Charge Shielding and Quark Confinement in the Massive Schwinger Model,Annals Phys.93(1975) 267
1975
-
[51]
Coleman,More About the Massive Schwinger Model,Annals Phys.101(1976) 239
S.R. Coleman,More About the Massive Schwinger Model,Annals Phys.101(1976) 239
1976
-
[52]
Polyakov,Microscopic Description of Critical Phenomena,Soviet Physics JETP28 (1969) 533
A.M. Polyakov,Microscopic Description of Critical Phenomena,Soviet Physics JETP28 (1969) 533
1969
-
[53]
Hubbard,Critical behaviour of the Ising model,Physics Letters A39(1972) 365
J. Hubbard,Critical behaviour of the Ising model,Physics Letters A39(1972) 365
1972
-
[54]
Wilson and J
K.G. Wilson and J. Kogut,The renormalization group and theϵexpansion,Physics Reports 12(1974) 75
1974
-
[55]
Cardy,The Yang-Lee Edge Singularity and Related Problems, 5, 2023 [2305.13288]
J. Cardy,The Yang-Lee Edge Singularity and Related Problems, 5, 2023 [2305.13288]
arXiv 2023
-
[56]
Kogut,An introduction to lattice gauge theory and spin systems,Rev
J.B. Kogut,An introduction to lattice gauge theory and spin systems,Rev. Mod. Phys.51 (1979) 659
1979
-
[57]
Cardy,Conformal invariance and universality in finite-size scaling,Journal of Physics A: Mathematical and General17(1984) L385
J.L. Cardy,Conformal invariance and universality in finite-size scaling,Journal of Physics A: Mathematical and General17(1984) L385
1984
-
[58]
Bl¨ ote, J.L
H.W.J. Bl¨ ote, J.L. Cardy and M.P. Nightingale,Conformal invariance, the central charge, and universal finite-size amplitudes at criticality,Phys. Rev. Lett.56(1986) 742
1986
-
[59]
Cardy,Operator content of two-dimensional conformally invariant theories,Nuclear Physics B270(1986) 186
J.L. Cardy,Operator content of two-dimensional conformally invariant theories,Nuclear Physics B270(1986) 186
1986
-
[60]
Wydro and J.F
T. Wydro and J.F. McCabe,Tests of conformal field theory at the Yang-Lee singularity, in AIP Conference Proceedings, p. 216–222, AIP, 2009, DOI
2009
-
[61]
Dotsenko and V.A
V.S. Dotsenko and V.A. Fateev,Operator Algebra of Two-Dimensional Conformal Theories with Central Charge C<= 1,Phys. Lett. B154(1985) 291
1985
-
[62]
Fishman, S.R
M. Fishman, S.R. White and E.M. Stoudenmire,The ITensor Software Library for Tensor Network Calculations,SciPost Phys. Codebases(2022) 4
2022
-
[63]
Fishman, S.R
M. Fishman, S.R. White and E.M. Stoudenmire,Codebase release 0.3 for ITensor,SciPost Phys. Codebases(2022) 4. – 45 –
2022
-
[64]
Bulirsch and J
R. Bulirsch and J. Stoer,Numerical treatment of ordinary differential equations by extrapolation methods,Numerische Mathematik8(1966) 1
1966
-
[65]
Henkel and G
M. Henkel and G. Schutz,Finite-lattice extrapolation algorithms,Journal of Physics A: Mathematical and General21(1988) 2617
1988
-
[66]
G.A. Starkov, M.V. Fistoul and I.M. Eremin,Quantum phase transitions in non-Hermitian PT-symmetric transverse-field Ising spin chains,Annals Phys.456(2023) 169268 [2211.00679]
arXiv 2023
-
[67]
Sen,Quantum phase transitions in the ising model in a spatially modulated field,Physical Review E63(2000) 016112
P. Sen,Quantum phase transitions in the ising model in a spatially modulated field,Physical Review E63(2000) 016112
2000
-
[68]
Fisher and M.N
M.E. Fisher and M.N. Barber,Scaling Theory for Finite-Size Effects in the Critical Region, Phys. Rev. Lett.28(1972) 1516
1972
-
[69]
Hamer and M.N
C.J. Hamer and M.N. Barber,Finite Lattice Methods in Quantum Hamiltonian Field Theory. 1. The Ising Model,J. Phys. A14(1981) 241
1981
-
[70]
Byrnes, P
T. Byrnes, P. Sriganesh, R. Bursill and C. Hamer,Density matrix renormalisation group approach to the massive Schwinger model,Nuclear Physics B - Proceedings Supplements109 (2002) 202–206
2002
-
[71]
Byrnes,Density Matrix Renormalization Group: A New Approach to Lattice Gauge Theory, University of New South Wales (2003)
T. Byrnes,Density Matrix Renormalization Group: A New Approach to Lattice Gauge Theory, University of New South Wales (2003)
2003
-
[72]
Buyens, S
B. Buyens, S. Montangero, J. Haegeman, F. Verstraete and K. Van Acoleyen, Finite-representation approximation of lattice gauge theories at the continuum limit with tensor networks,Phys. Rev. D95(2017) 094509
2017
-
[73]
H. Ohata,Phase diagram near the quantum critical point in Schwinger model atθ=π: analogy with quantum Ising chain,PTEP2024(2024) 013B02 [2311.04738]
arXiv 2024
-
[74]
Dempsey, I.R
R. Dempsey, I.R. Klebanov, S.S. Pufu and B. Zan,Discrete chiral symmetry and mass shift in the lattice Hamiltonian approach to the Schwinger model,Phys. Rev. Res.4(2022) 043133
2022
-
[75]
R. Dempsey, I.R. Klebanov, S.S. Pufu, B.T. Søgaard and B. Zan,Phase Diagram of the Two-Flavor Schwinger Model at Zero Temperature,Phys. Rev. Lett.132(2024) 031603 [2305.04437]
arXiv 2024
-
[76]
E. Arguello Cruz, G. Tarnopolsky and Y. Xin,Precision study of the massive Schwinger model near quantum criticality,Phys. Rev. D112(2025) 034023 [2412.01902]
arXiv 2025
-
[77]
G. Cuomo, R. Dempsey, A. Katsevich, I.R. Klebanov, I.V. Kochergin, S.S. Pufu et al.,The two-flavor Schwinger model at 50: Solving Coleman’s puzzles,2605.08042
- [78]
-
[79]
Kogut and L
J. Kogut and L. Susskind,Hamiltonian formulation of wilson’s lattice gauge theories,Phys. Rev. D11(1975) 395
1975
-
[80]
Banks, L
T. Banks, L. Susskind and J. Kogut,Strong-coupling calculations of lattice gauge theories: (1 + 1)-dimensional exercises,Phys. Rev. D13(1976) 1043
1976
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