Pietro Longhi
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
Pietro Longhi has a total of 42 co-authors. Here are the top co-authors by number of shared publications:
- Tobias Ekholm
Department of Mathematics, Uppsala University, Box 480, 751 06 Uppsala, Sweden
11 shared publications - Mauricio Romo
Yau Mathematical Sciences Center, Tsinghua University, Beijing, China
6 shared publications - Nathaniel Craig
University of California
6 shared publications - Simon Knapen
Lawrence Berkeley National Laboratory
6 shared publications - Chan Y. Park
KC Machine Learning Lab 06181 Seoul Republic of Korea
5 shared publications - Piotr Kucharski
Institute of Mathematics, University of Warsaw, Warsaw, Poland
5 shared publications
Latest Publications
- Open Access
- 5 November 2026
- Published by Springer Nature in Letters in Mathematical Physics
- Vol. 116 (6) , 152
Open strings on knot complements
Using skein-valued holomorphic curve counting techniques, we give a flow loop formula for the skein-valued partition function of the Lagrangian knot complement of a fibered knot (of the A -model open topological strings with Lagrangian A -branes wrapping the complement) in the cotangent bundle of the three-sphere and in the resolved conifold. For torus knots, we show that the partition function in the cotangent bundle localizes on two or three holomorphic annuli and give a corresponding generalized quiver structure for the partition function in the resolved conifold. We connect the formula to the augmentation curve, the representation variety of the knot contact homology algebra of the knot, generated by Reeb chords of its Legendrian conormal and with differential given by holomorphic disks interpolating between words of Reeb chords. The curve admits a quantization as a q -difference equation for the generating function of symmetrically colored HOMFLYPT-polynomials of the knot or, geometrically, for the U (1)-partition function of the knot conormal. For $$(2,2p+1)$$ -torus knots, we show that, after a change of variables, the partition function of the knot complement also satisfies this q -difference equation. This gives another geometrically defined coordinate chart for the D -module defined by the quantized augmentation polynomial.- 5 November 2026
- Published by Springer Nature in Letters in Mathematical Physics
- Vol. 116 (6) , 152
Open AccessOpen strings on knot complements
Using skein-valued holomorphic curve counting techniques, we give a flow loop formula for the skein-valued partition function of the Lagrangian knot complement of a fibered knot (of the A -model open topological strings with Lagrangian A -branes wrapping the complement) in the cotangent bundle of the three-sphere and in the resolved conifold. For torus knots, we show that the partition function in the cotangent bundle localizes on two or three holomorphic annuli and give a corresponding generalized quiver structure for the partition function in the resolved conifold. We connect the formula to the augmentation curve, the representation variety of the knot contact homology algebra of the knot, generated by Reeb chords of its Legendrian conormal and with differential given by holomorphic disks interpolating between words of Reeb chords. The curve admits a quantization as a q -difference equation for the generating function of symmetrically colored HOMFLYPT-polynomials of the knot or, geometrically, for the U (1)-partition function of the knot conormal. For $$(2,2p+1)$$ -torus knots, we show that, after a change of variables, the partition function of the knot complement also satisfies this q -difference equation. This gives another geometrically defined coordinate chart for the D -module defined by the quantized augmentation polynomial. - Open Access
- 28 October 2026
- Published by Springer Nature in Communications in Mathematical Physics
- Vol. 407 (12) , 258
The Worldsheet Skein D-module and Basic Curves on Lagrangian Fillings of the Hopf Link Conormal
HOMFLYPT polynomials of knots in the 3-sphere in symmetric representations satisfy recursion relations. Their geometric origin is holomorphic curves at infinity on knot conormals that determine a D -module with characteristic variety the Legendrian knot conormal augmention variety and with the recursion relations as operator polynomial generators [1, 2]. We consider skein lifts of recursions and D -modules corresponding to skein valued open curve counts [3] that encode HOMFLYPT polynomials colored by arbitrary partitions. We define a worldsheet skein module which is the universal target for skein curve counts and a corresponding D -module. We then consider the concrete example of the Legendrian conormal of the Hopf link. We show that the worldsheet skein D -module for the Hopf link conormal is generated by three operator polynomials that annihilate the skein valued partition function for any choice of Lagrangian filling and recursively determine it uniquely. We find Lagrangian fillings for any point in the augmentation variety and show that their skein valued partition functions admit quiver-like expansions where all holomorphic curves are generated by a small number of basic holomorphic disks and annuli and their multiple covers.
- 28 October 2026
- Published by Springer Nature in Communications in Mathematical Physics
- Vol. 407 (12) , 258
Open AccessThe Worldsheet Skein D-module and Basic Curves on Lagrangian Fillings of the Hopf Link Conormal
HOMFLYPT polynomials of knots in the 3-sphere in symmetric representations satisfy recursion relations. Their geometric origin is holomorphic curves at infinity on knot conormals that determine a D -module with characteristic variety the Legendrian knot conormal augmention variety and with the recursion relations as operator polynomial generators [1, 2]. We consider skein lifts of recursions and D -modules corresponding to skein valued open curve counts [3] that encode HOMFLYPT polynomials colored by arbitrary partitions. We define a worldsheet skein module which is the universal target for skein curve counts and a corresponding D -module. We then consider the concrete example of the Legendrian conormal of the Hopf link. We show that the worldsheet skein D -module for the Hopf link conormal is generated by three operator polynomials that annihilate the skein valued partition function for any choice of Lagrangian filling and recursively determine it uniquely. We find Lagrangian fillings for any point in the augmentation variety and show that their skein valued partition functions admit quiver-like expansions where all holomorphic curves are generated by a small number of basic holomorphic disks and annuli and their multiple covers.
- Open Access
- 28 August 2026
- Published by Springer Nature in Communications in Mathematical Physics
- Vol. 407 (10) , 206
Quivers and BPS States in 3d and 4d
We propose a symmetrization relation between BPS quivers encoding 4d $$\mathcal {N}=2$$ theories and symmetric quivers associated to 3d $$\mathcal {N}=2$$ theories. We analyse in detail the symmetrization of BPS quivers for a series of $$A_m$$ Argyres-Douglas theories by engineering 3d-4d systems in geometric backgrounds involving appropriate 3-manifolds and Riemann surfaces. We discuss properties of these geometric backgrounds and derive the corresponding quiver partition functions from the perspective of skein modules, which forms the foundation of the symmetrization map for the minimal chamber. We also prove that the structure of wall-crossing in 4d $$A_m$$ Argyres-Douglas theories is isomorphic to the structure of unlinking of symmetric quivers encoding their partner 3d theories, which allows for a proper definition of the symmetrization map outside the minimal chamber. Finally, we show that the Schur indices of 4d theories are captured by symmetric quivers that include symmetrization of 4d BPS quivers.- 28 August 2026
- Published by Springer Nature in Communications in Mathematical Physics
- Vol. 407 (10) , 206
Open AccessQuivers and BPS States in 3d and 4d
We propose a symmetrization relation between BPS quivers encoding 4d $$\mathcal {N}=2$$ theories and symmetric quivers associated to 3d $$\mathcal {N}=2$$ theories. We analyse in detail the symmetrization of BPS quivers for a series of $$A_m$$ Argyres-Douglas theories by engineering 3d-4d systems in geometric backgrounds involving appropriate 3-manifolds and Riemann surfaces. We discuss properties of these geometric backgrounds and derive the corresponding quiver partition functions from the perspective of skein modules, which forms the foundation of the symmetrization map for the minimal chamber. We also prove that the structure of wall-crossing in 4d $$A_m$$ Argyres-Douglas theories is isomorphic to the structure of unlinking of symmetric quivers encoding their partner 3d theories, which allows for a proper definition of the symmetrization map outside the minimal chamber. Finally, we show that the Schur indices of 4d theories are captured by symmetric quivers that include symmetrization of 4d BPS quivers. - Open Access
- 3 February 2026
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2026 (2) , 33
Modelling A-branes with foliations
A bstract: A certain class of A -branes in mirrors of toric Calabi-Yau threefolds can be described through the framework of foliations. This allows to develop an explicit description of their moduli spaces based on a cell decomposition, with strata of various dimensions glued together in a way that is dictated by partial degenerations of the underlying special Lagrangian. Examples of A -branes associated with ‘wild’ BPS states are considered in detail. The torus fixed points in their moduli spaces provide a decomposition of m -herds spectral networks into a number |Ω| of basic connected objects, where Ω is the corresponding rank-zero Donaldson-Thomas (DT) invariant. A relation between the surgery parameters of the special Lagrangian and the baryonic semi-invariants of the representation theory of m -Kronecker quivers is also discussed, providing a local map between moduli spaces of branes related by homological mirror symmetry.
- 3 February 2026
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2026 (2) , 33
Open AccessModelling A-branes with foliations
A bstract: A certain class of A -branes in mirrors of toric Calabi-Yau threefolds can be described through the framework of foliations. This allows to develop an explicit description of their moduli spaces based on a cell decomposition, with strata of various dimensions glued together in a way that is dictated by partial degenerations of the underlying special Lagrangian. Examples of A -branes associated with ‘wild’ BPS states are considered in detail. The torus fixed points in their moduli spaces provide a decomposition of m -herds spectral networks into a number |Ω| of basic connected objects, where Ω is the corresponding rank-zero Donaldson-Thomas (DT) invariant. A relation between the surgery parameters of the special Lagrangian and the baryonic semi-invariants of the representation theory of m -Kronecker quivers is also discussed, providing a local map between moduli spaces of branes related by homological mirror symmetry.
- Open Access
Open strings on knot complements
Using skein valued holomorphic curve counting techniques, we give a flow loop formula for the skein valued partition function of the Lagrangian knot complement of a fibered knot (of the $A$-model open topological strings with Lagrangian $A$-branes wrapping the complement) in the cotangent bundle of the three-sphere and in the resolved conifold. For torus knots we show that the partition function in the cotangent bundle localizes on two or three holomorphic annuli and give a corresponding generalized quiver structure for the partition function in the resolved conifold. We connect the formula to the augmentation curve, the representation variety of the knot contact homology algebra of the knot, generated by Reeb chords of its Legendrian conormal and with differential given by holomorphic disks interpolating between words of Reeb chords. The curve admits a quantization as a $q$-difference equation for the generating function of symmetrically colored HOMFLYPT-polynomials of the knot or, geometrically, for the $U(1)$-partition function of the knot conormal. For $(2,2p+1)$-torus knots we show that, after a change of variables, the partition function of the knot complement also satisfies this $q$-difference equation. This gives another geometrically defined coordinate chart for the $D$-module defined by the quantized augmentation polynomial.
Open AccessOpen strings on knot complements
Using skein valued holomorphic curve counting techniques, we give a flow loop formula for the skein valued partition function of the Lagrangian knot complement of a fibered knot (of the $A$-model open topological strings with Lagrangian $A$-branes wrapping the complement) in the cotangent bundle of the three-sphere and in the resolved conifold. For torus knots we show that the partition function in the cotangent bundle localizes on two or three holomorphic annuli and give a corresponding generalized quiver structure for the partition function in the resolved conifold. We connect the formula to the augmentation curve, the representation variety of the knot contact homology algebra of the knot, generated by Reeb chords of its Legendrian conormal and with differential given by holomorphic disks interpolating between words of Reeb chords. The curve admits a quantization as a $q$-difference equation for the generating function of symmetrically colored HOMFLYPT-polynomials of the knot or, geometrically, for the $U(1)$-partition function of the knot conormal. For $(2,2p+1)$-torus knots we show that, after a change of variables, the partition function of the knot complement also satisfies this $q$-difference equation. This gives another geometrically defined coordinate chart for the $D$-module defined by the quantized augmentation polynomial.
- Open Access
Skein traces from curve counting
Given a 3-manifold $M$, and a branched cover arising from the projection of a Lagrangian 3-manifold $L$ in the cotangent bundle of $M$ to the zero-section, we define a map from the skein of $M$ to the skein of $L$, via the skein-valued counting of holomorphic curves. When $M$ and $L$ are products of surfaces and intervals, we show that wall crossings in the space of the branched covers obey a skein-valued lift of the Kontsevich-Soibelman wall-crossing formula. Holomorphic curves in cotangent bundles correspond to Morse flow graphs; in the case of branched double covers, this allows us to give an explicit formula for the the skein trace. After specializing to the case where $M$ is a surface times an interval, and additionally specializing the HOMFLYPT skein to the $\mathfrak{gl}(2)$ skein on $M$ and the $\mathfrak{gl}(1)$ skein on $L$, we recover an existing prescription of Neitzke and Yan.Open AccessSkein traces from curve counting
Given a 3-manifold $M$, and a branched cover arising from the projection of a Lagrangian 3-manifold $L$ in the cotangent bundle of $M$ to the zero-section, we define a map from the skein of $M$ to the skein of $L$, via the skein-valued counting of holomorphic curves. When $M$ and $L$ are products of surfaces and intervals, we show that wall crossings in the space of the branched covers obey a skein-valued lift of the Kontsevich-Soibelman wall-crossing formula. Holomorphic curves in cotangent bundles correspond to Morse flow graphs; in the case of branched double covers, this allows us to give an explicit formula for the the skein trace. After specializing to the case where $M$ is a surface times an interval, and additionally specializing the HOMFLYPT skein to the $\mathfrak{gl}(2)$ skein on $M$ and the $\mathfrak{gl}(1)$ skein on $L$, we recover an existing prescription of Neitzke and Yan. - Open Access
- 24 July 2025
- Published by Springer Nature in Annales Henri Poincare
- Vol. 27 (7) , 1-51
Linking Disks, Spinning Vortices and Exponential Networks of Augmentation Curves
We propose a mirror derivation of the quiver description of open topological strings known as the knots-quivers correspondence, based on enumerative invariants of augmentation curves encoded by exponential networks. Quivers are obtained by studying M2 branes wrapping holomorphic disks with Lagrangian boundary conditions on an M5 brane, through their identification with a distinguished sector of BPS kinky vortices in the 3d-3d dual QFT. Our proposal suggests that holomorphic disks with Lagrangian boundary conditions are mirror to calibrated 1-chains on the associated augmentation curve, whose intersections encode the linking of boundaries.
- 24 July 2025
- Published by Springer Nature in Annales Henri Poincare
- Vol. 27 (7) , 1-51
Open AccessLinking Disks, Spinning Vortices and Exponential Networks of Augmentation Curves
We propose a mirror derivation of the quiver description of open topological strings known as the knots-quivers correspondence, based on enumerative invariants of augmentation curves encoded by exponential networks. Quivers are obtained by studying M2 branes wrapping holomorphic disks with Lagrangian boundary conditions on an M5 brane, through their identification with a distinguished sector of BPS kinky vortices in the 3d-3d dual QFT. Our proposal suggests that holomorphic disks with Lagrangian boundary conditions are mirror to calibrated 1-chains on the associated augmentation curve, whose intersections encode the linking of boundaries.
- Top Cited PapersOpen Access
- 23 June 2025
- Published by Springer Nature in Communications in Mathematical Physics
- Vol. 406 (7) , 1-85
Exponential BPS Graphs and D-Brane Counting on Toric Calabi–Yau Threefolds: Part II
We study BPS states of 5d $$\mathcal {N}=1$$ SU(2) Yang-Mills theory on $$S^1\times \mathbb {R}^4$$ . Geometric engineering relates these to enumerative invariants for the local Hirzebruch surface $$\mathbb {F}_0$$ . We illustrate computations of Vafa-Witten invariants via exponential networks, verifying fiber-base symmetry of the spectrum at certain points in moduli space, and matching with mirror descriptions based on quivers and exceptional collections. Albeit infinite, parts of the spectrum organize in families described by simple algebraic equations. Varying the radius of the M-theory circle interpolates smoothly with the spectrum of 4d $$\mathcal {N}=2$$ Seiberg–Witten theory, recovering spectral networks in the limit.- 23 June 2025
- Published by Springer Nature in Communications in Mathematical Physics
- Vol. 406 (7) , 1-85
Top Cited PapersOpen AccessExponential BPS Graphs and D-Brane Counting on Toric Calabi–Yau Threefolds: Part II
We study BPS states of 5d $$\mathcal {N}=1$$ SU(2) Yang-Mills theory on $$S^1\times \mathbb {R}^4$$ . Geometric engineering relates these to enumerative invariants for the local Hirzebruch surface $$\mathbb {F}_0$$ . We illustrate computations of Vafa-Witten invariants via exponential networks, verifying fiber-base symmetry of the spectrum at certain points in moduli space, and matching with mirror descriptions based on quivers and exceptional collections. Albeit infinite, parts of the spectrum organize in families described by simple algebraic equations. Varying the radius of the M-theory circle interpolates smoothly with the spectrum of 4d $$\mathcal {N}=2$$ Seiberg–Witten theory, recovering spectral networks in the limit. - Open Access
- 29 January 2025
- Published by Springer Nature in Annales Henri Poincare
- Vol. 26 (12) , 4271-4365
From Quantum Curves to Topological String Partition Functions II
We propose a geometric characterisation of the topological string partition functions associated with the local Calabi–Yau (CY) manifolds used in the geometric engineering of $$d=4$$ , $${\mathcal {N}}=2$$ supersymmetric field theories of class $${\mathcal {S}}$$ . A quantisation of these CY manifolds defines differential operators called quantum curves. The partition functions are extracted from the isomonodromic tau-functions associated with the quantum curves by expansions of generalised theta series type. It turns out that the partition functions are in one-to-one correspondence with preferred coordinates on the moduli spaces of quantum curves defined using the Exact WKB method. The coordinates defined in this way jump across certain loci in the moduli space. The changes of normalization of the tau-functions associated with these jumps define a natural line bundle playing a key role in the geometric characterisation of the topological string partition functions proposed here.- 29 January 2025
- Published by Springer Nature in Annales Henri Poincare
- Vol. 26 (12) , 4271-4365
Open AccessFrom Quantum Curves to Topological String Partition Functions II
We propose a geometric characterisation of the topological string partition functions associated with the local Calabi–Yau (CY) manifolds used in the geometric engineering of $$d=4$$ , $${\mathcal {N}}=2$$ supersymmetric field theories of class $${\mathcal {S}}$$ . A quantisation of these CY manifolds defines differential operators called quantum curves. The partition functions are extracted from the isomonodromic tau-functions associated with the quantum curves by expansions of generalised theta series type. It turns out that the partition functions are in one-to-one correspondence with preferred coordinates on the moduli spaces of quantum curves defined using the Exact WKB method. The coordinates defined in this way jump across certain loci in the moduli space. The changes of normalization of the tau-functions associated with these jumps define a natural line bundle playing a key role in the geometric characterisation of the topological string partition functions proposed here. - Open Access
The skein valued mirror of the topological vertex
We count holomorphic curves in complex 3-space with boundaries on three special Lagrangian solid tori. The count is valued in the HOMFLYPT skein module of the union of the tori. Using 1-parameter families of curves at infinity, we derive three skein valued operator equations which must annihilate the count, and which dequantize to a mirror of the geometry. We show algebraically that the resulting equations determine the count uniquely, and that the result agrees with the topological vertex from topological string theory.
Open AccessThe skein valued mirror of the topological vertex
We count holomorphic curves in complex 3-space with boundaries on three special Lagrangian solid tori. The count is valued in the HOMFLYPT skein module of the union of the tori. Using 1-parameter families of curves at infinity, we derive three skein valued operator equations which must annihilate the count, and which dequantize to a mirror of the geometry. We show algebraically that the resulting equations determine the count uniquely, and that the result agrees with the topological vertex from topological string theory.