Chapter V: Higher rank
5.3 Symmetric representations and large π
We conjecture the following surgery formula analogous to [GM21, Conjecture 1.7]
relatingπΉπ€
πΎ to Λππ€
π3 π/π(πΎ),π
(π):
Conjecture 5.2.4(Higher rank surgery formula). LetπΎ β π3be a knot. Then Λ
ππ€
π3
π/π(πΎ),π(π) L(π/ππ)
"
Γ
πΌβΞ+
(π₯
πΌ 2π βπ₯β
πΌ 2π)πΉπ€
πΎ(x, π)
#
(5.29) wheneverβπ
π is big enough so that the right-hand side converges.
This is a theorem for knots and 3-manifolds represented by negative-definite plumb- ings, as a straightforward generalization of Theorem 1.2 of [GM21]. For instance, surgery on3π
1gives us the following Λππ°π©3βs:
π π3
β1/π(3π
1) πΛπ°π©3
π3
β1/π(3π
1)(π)
1 Ξ£(2,3,7) 1β2π+2π3+π4β2π5β2π8+4π9+2π10β4π11+2π13β6π14+ Β· Β· Β· 2 Ξ£(2,3,13) 1β2π+2π3βπ4+2π10β2π11β2π14+2π16+2π19β2π20+4π21β Β· Β· Β· 3 Ξ£(2,3,19) 1β2π+2π3βπ4+2π16β2π17β2π20+2π22+2π25β2π26+4π33β Β· Β· Β· 4 Ξ£(2,3,25) 1β2π+2π3βπ4+2π22β2π23β2π26+2π28+2π31β2π32+4π45β Β· Β· Β· 5 Ξ£(2,3,31) 1β2π+2π3βπ4+2π28β2π29β2π32+2π34+2π37β2π38+4π57β Β· Β· Β· π Ξ£(2,3,6π+1) Γ
(π€
1,π€
2)βπ2(β1)π(π€1π€2)π
36π+6,3(6π+1)π€
1(π)+2(6π+1)π€
2(π)+6π
In fact it is easy to check that forπΎ =ππ ,π‘, Lβ1/π
"
Γ
πΌβΞ+
(π₯
πΌ 2π βπ₯β
πΌ
2π)πΉπΎ(x, π)
#
βοΈ
(π€
1,π€
2)βπ2
(β1)π(π€1π€2)ππ π‘(π π π‘+
1),π‘(π π π‘+1)π€1(π)+π (π π π‘+1)π€2(π)+π π‘ π(π) πΛπ€
Ξ£(π ,π‘ ,π π π‘+1)(π),
which is consistent with what we have seen in Proposition5.1.6.
5.3 Symmetric representations and largeπ
Then the (reduced) symmetrically coloredπΉπΎ corresponds to the following special- ization:
πΉsym
πΎ (π₯ , π) :=πΉred
πΎ ( (π₯ , π,Β· Β· Β· , π), π). (5.31) That is, we set π₯
1 = π₯ and π₯
2 = Β· Β· Β· = π₯πβ
1 = π. A version of quantum volume conjecture [FGS13] states that this should be annihilated by the symmetrically colored quantum A-polynomial:
Λ
π΄πΎ(π₯ ,Λ π¦, πΛ =ππ, π)πΉπ°π©π
,sym
πΎ (π₯ , π) =0. (5.32) Example 5.3.1. Right-handed trefoil. For the right-handed trefoil,πΉπ°π©π
,sym 3π
1
(π₯ , π) for the first few values ofπ look like the following:
β’ Forπ°π©2, πΉπ°π©2
,sym 3π
1
(π₯ , π) 1 2
(βπ+π2+π3βπ6βπ8+π13+π16β Β· Β· Β· ) + (π₯+π₯β1) (π2+π3βπ6βπ8+π13+π16β Β· Β· Β· ) + (π₯2+π₯β2) (π2+π3βπ6βπ8+π13+π16β Β· Β· Β· ) + (π₯3+π₯β3) (π3βπ6βπ8+π13+π16β Β· Β· Β· ) + (π₯4+π₯β4) (βπ6βπ8+π13+π16β Β· Β· Β· ) + Β· Β· Β· ];
β’ Forπ°π©3, πΉπ°π©3
,sym 3π
1
(π₯ , π) 1 2
(β2πβ2π2+2π4+4π5+4π6+4π7+2π8β2π10β4π11β Β· Β· Β· ) + (π1/2π₯+πβ1/2π₯β1)π1/2(β1β2πβπ2+π3+3π4+4π5+4π6+ Β· Β· Β· ) + (ππ₯2+πβ1π₯β2) (βπβπ2+2π4+3π5+4π6+3π7+2π8β2π10+ Β· Β· Β· ) + (π3/2π₯3+πβ3/2π₯β3)π1/2(π3+2π4+3π5+3π6+2π7+π8+ Β· Β· Β· ) + (π2π₯4+πβ2π₯β4) (π3+π4+2π5+2π6+2π7+π8+ Β· Β· Β· )
+ Β· Β· Β· ];
β’ Forπ°π©4, πΉπ°π©4
,sym 3π
1
(π₯ , π) 1 2
(πβ2+πβ1β2β4πβ8π2β7π3β7π4+ Β· Β· Β· )
+ (ππ₯+πβ1π₯β1) (πβ2β1β5πβ6π2β8π3β5π4β2π5+ Β· Β· Β· ) + (π2π₯2+πβ2π₯β2) (β2β3πβ6π2β5π3β5π4+4π6+ Β· Β· Β· )
+ (π3π₯3+πβ3π₯β3) (βπβ1β1β3πβ3π2β4π3β2π4+5π6+9π7+ Β· Β· Β· ) + (π4π₯4+πβ4π₯β4) (β1βπβ2π2βπ3βπ4+2π5+4π6+8π7+ Β· Β· Β· ) + Β· Β· Β· ].
Note that the overall factor is 12 instead of π1!. This is due to reduction of the Weyl symmetry toZ2as we specialize to symmetric representations.
It is easy to experimentally check (5.32) term by term in this case, using the π-deformed quantum π΄-polynomial for the right-handed trefoil
Λ π΄3π
1
(π₯ ,Λ π¦, π, πΛ ) =π
0+π
1π¦Λ+π
2π¦Λ2, where
π0=β (β1+π₯Λ) (β1+π ππ₯Λ2) ππ₯Λ3(β1+ππ₯Λ) (βπ+ππ₯Λ2),
π1= (β1+ππ₯Λ2) (βπ2π₯Λ2+π π3π₯Λ2+π ππ₯Λ(1+π₯Λ+π(β1+π₯Λ)π₯Λ) βπ2(1+π2π₯Λ4)) π2ππ₯Λ3(β1+ππ₯Λ) (βπ+ππ₯Λ2) , π2=1
withπspecialized toππ. Large-π
From (5.32), we are naturally led to the following conjecture:
Conjecture 5.3.2([Par20a]). For each knotπΎ, there exists a function πΉπΎ(π₯ , π, π) such that
Λ
π΄πΎ(π₯ ,Λ π¦, π, πΛ )πΉπΎ(π₯ , π, π)=0 (5.33) and
πΉπΎ(π₯ , ππ, π) =πΉπ°π©π
,sym
πΎ (π₯ , π) (5.34)
for anyπ. Moreover, this function should have the following Weyl symmetry:
πΉπΎ(π₯β1, π, π) =πΉπΎ(πβ1π2π₯ , π, π). (5.35)
In particular, (5.34) implies
πβlim1
πΉπΎ(π₯ , ππ, π) = ΞπΎ(π₯)1βπ. (5.36) The study of this HOMFLY-PT analogue (i.e.,π-deformation) ofπΉπΎ is the subject of next chapter.
Remark 5.3.3. This conjecture has been checked for various knots [Ekh+;Ekh+22], by either solving the quantumπ΄-polynomial equation, or by using theπ -matrix state sum and then using the knots-quivers correspondence to find theπ-deformation.
C h a p t e r 6
TOPOLOGICAL STRINGS
At the end of the previous chapter, we presented a conjecture on the existence of a three- variable seriesπΉπΎ(π₯ , π, π) that interpolatesπΉπΎβs forπ°π©π. In this chapter, following [Ekh+;Ekh+22], we explain how this three-variable series can be interpreted as a topological string partition function. As we will see, this will lead to several concrete mathematical predictions.
6.1 Topological strings andπΉπΎ HOMFLY-PT polynomials
For a knotπΎ β π3, itsHOMFLY-PT polynomialis a topological invariant [Hos+85;
PT87] which can be defined by the skein relation
π1/2π (π, π) βπβ1/2π (π, π) = (π1/2βπβ1/2)π (π, π) with a normalization condition π
01(π, π) = 1 for the unknot. The HOMFLY-PT polynomial interpolates all theπ°π©π Jones polynomialsπ½π°π©π
πΎ (π)in the sense that ππΎ(π=ππ, π) = π½π°π©π
πΎ (π).
More generally, thecolored HOMFLY-PT polynomialsππΎ , π (π, π)are polynomial knot invariants generalizing the HOMFLY-PT polynomial, which also depends on a representation (a Young diagram)π . The colored HOMFLY-PT polynomial ππΎ , π (π, π)interpolates the coloredπ°π©π Jones polynomials in the sense that
ππΎ , π (π=ππ, π) = π½π°π©π
πΎ , π (π).
The original HOMFLY-PT polynomial corresponds to the case of defining represen- tationπ =β‘. We will be interested mainly in the HOMFLY-PT polynomials colored by the totally symmetric representations
π =ππ =β‘| {z Β· Β· Β·β‘}
π
withπ boxes in a row in the Young diagram. In order to simplify the notation, we will denote them by ππΎ ,π(π, π)and call them simply the HOMFLY-PT polynomials.
There is also a π‘-deformation of the HOMFLY-PT polynomials [DGR06;GS12a].
The superpolynomial PπΎ ,π(π, π, π‘) is defined as the PoincarΓ© polynomial of the triply-graded homology that categorifies the HOMFLY-PT polynomial:
ππΎ ,π(π, π) =βοΈ
π, π , π
(β1)πππππdimHπ, π , πππ (πΎ), PπΎ ,π(π, π, π‘) =βοΈ
π, π , π
πππππ‘πdimHππ
π, π , π(πΎ).
(6.1)
The superpolynomial reduces to the HOMFLY-PT polynomial whenπ‘ =β1:
PπΎ ,π(π, π, π‘ =β1) = ππΎ ,π(π, π). π΄-polynomials
The π΄-polynomial π΄πΎ(π₯ , π¦) is a polynomial knot invariant defining the algebraic curve {(π₯ , π¦) β (Cβ)2 | π΄πΎ(π₯ , π¦) = 0}, which is the projection of the character variety of the the knot complement to the boundary torus [Coo+94]. According to the volume conjecture, it also captures the asymptotics of the colored Jones polynomials π½πΎ ,π(π)for large colorsπ. The quantization of the π΄-polynomial encodes information about all colors, not only large ones. Namely, it gives the recurrence relations satisfied by the colored Jones polynomialsπ½π(πΎ;π):
Λ
π΄πΎ(π₯ ,Λ π¦, πΛ )π½πΎ ,π(π) =0, where Λπ₯and Λπ¦act by
Λ
π₯ π½πΎ ,π(π) =πππ½πΎ ,π(π), π¦ π½Λ πΎ ,π(π) =π½πΎ ,π+
1(π),
and satisfy the π-commutation relation Λπ¦π₯Λ = ππ₯Λπ¦Λ. The π-difference operator Λ
π΄πΎ(π₯ ,Λ π¦, πΛ ), which we have already seen many times in previous chapters, is called the quantum π΄-polynomial; in the classical limit π = 1 it becomes the usual π΄- polynomial π΄πΎ(π₯ , π¦). The existence of the quantum π΄-polynomial was conjectured independently in the context of quantization of the Chern-Simons theory [Guk05]
and in parallel mathematics developments [Gar04].
The π΄-polynomial can be generalized further for the colored HOMFLY-PT polyno- mials [AV12] and colored superpolynomials [Awa+12;FGS13], which we briefly introduced in (6.1). In these cases the objects mentioned in the previous paragraph becomeπ- andπ‘-dependent. In particular, the asymptotics of colored superpolyno- mialsPπ(πΎ;π, π, π‘)for largeπ is captured by an algebraic curve π΄πΎ(π₯ , π¦, π, π‘) =0 defined by the super-π΄-polynomial. When π‘ = β1 it becomes the π-deformed
π΄-polynomial, and upon setting in additionπ = 1, it gets reduced further to the originalπ΄-polynomial (as a factor). For brevity, all these objects are often referred to asπ΄-polynomials. The quantization of the super-π΄-polynomial gives rise to quantum super-π΄-polynomial Λπ΄πΎ(π₯ ,Λ π¦, π, π, π‘Λ ), which is aπ-difference operator that encodes the recurrence relations for the colored superpolynomials:
Λ
π΄πΎ(π₯ ,Λ π¦, π, π, π‘Λ )Pβ(πΎ;π, π, π‘) =0.
A universal framework that enables us to determine a quantum π΄-polynomial from an underlying classical curve π΄(π₯ , π¦) =0 was proposed in [GS12b] (irrespective of extra parameters these curves depend on, and also beyond examples related to knots).
Large-π transition
In this subsection we explain the physical background in order to motivate the conjectures that we will present in later sections. The mathematically inclined readers may skip this subsection.
The physical system we are interested in1 can be represented by the system of π fivebranes supported onR2Γπ1Γπ, whereπ is embedded as the zero-section inside the Calabi-Yau 3-foldπβπ andR2Γπ1 β R4Γπ1:
spacetime : R4Γπ1Γπβπ
βͺ βͺ
π M5-branes : R2Γπ1Γπ .
(6.2)
Finding the large-π limit of this system for general 3-manifoldπ is highly nontrivial (see [GPV17, sec.7] and [ES19, Remark 2.4]). However, whenπis a knot complement ππΎ := π3\πΎ, there is an equivalent description for which the study of large-π behavior can be reduced to the celebrated βlarge-π transitionβ [GV98;OV00].
We consider first a description without transition. From the viewpoint of 3d/3d correspondence,π fivebranes onπ = ππΎ produce a 4dN =4 theory β which is a close cousin of (but isnot) 4dN =4 super-Yang-Mills β on a half-spaceR3ΓR+
coupled to 3dN =2 theoryπ[ππΎ] on the boundary. Indeed, near the boundary π2= ΞπΎ =π ππΎ, the compactification ofπ fivebranes produces a 4dN =4 theory which has moduli space of vacua Symπ(C2ΓCβ) [Chu+20]. (The moduli space of vacua in 4dN =4 SYM is Symπ(C3).) The ππ(π) gauge symmetry of this theory appears as a global symmetry of the 3d boundary theoryπ[ππΎ]. In particular, the
1We have already reviewed this briefly in Section2.2.
variablesπ₯π βCβare complexified fugacities for this global (βflavorβ) symmetry. For πΊ = ππ(2), the moduli space of vacua of the knot complement theoryππ°π©
2[ππΎ] gives precisely the π΄-polynomial ofπΎ. Similarly, forπΊ = ππ(π), πΊ
C character varieties ofππΎ are realized as spaces of vacua inππ°π©
π[ππΎ][FGS13;Fuj+13].
We next give another equivalent description of the physical system (6.2) withπ =ππΎ, where the large-π behavior is easier to analyze:
spacetime : R4Γπ1Γπβπ3
βͺ βͺ
π M5-branes : R2Γπ1Γπ3 πM5β²-branes : R2Γπ1ΓπΏπΎ.
(6.3)
This brane configuration is basically a variant of (6.2) withπ = π3 and π extra M5-branes supported onR2Γπ1ΓπΏπΎ, whereπΏπΎ β πβπ3is the conormal bundle of the knotπΎ β π3(often called theknot conormal Lagrangian). There is, however, a crucial difference between fivebranes onπ3andπΏπΎ. Since the latter are non-compact in two directions orthogonal to πΎ, they carry no dynamical degrees of freedom away from πΎ. One can path integrate those degrees of freedom along πΎ, which effectively removesπΎ fromπ3and puts the corresponding boundary conditions on the boundaryπ2 = π ππΎ. The resulting system is precisely (6.2) withπ = ππΎ. Equivalently, one can use the topological invariance alongπ3to move the tubular neighbourhood of πΎ β π3 to βinfinity.β This creates a long neck isomorphic to RΓπ2, as in the above discussion. Either way, we end up with a system of π fivebranes on the knot complement and no extra branes on πΏπΎ, so that the choice ofπΊ πΏ(π,C) flat connection onπΏπΎ is now encoded in the boundary condition for π πΏ(π ,C)connection2onπ2=π ππΎ. In particular, the latter has at mostπnontrivial parametersπ₯π βCβ,π =1, . . . , π.
We will consider the simplest case ofπ =1. Then we can use the geometric transition of [GV98], upon which there is one brane onπΏπΎandπfivebranes on the zero-section of πβπ3 disappear. The Calabi-Yau space πβπ3 undergoes a topology changing transition to a new Calabi-Yau space π, the so-called βresolved conifoldβ, which is the total space ofO (β1) β O (β1) βCP1, and only the Ooguri-Vafa fivebranes
2To be more precise, it is aπΊ πΏ(π ,C)connection, but the dynamics of theπΊ πΏ(1,C)sector is different from that of theπ πΏ(π ,C)sector and can be decoupled.
supported on the conormal bundleπΏπΎ remain:
spacetime : R4Γπ1Γ π
βͺ βͺ
πM5β²-branes : R2Γπ1Γ πΏπΎ.
(6.4)
Note that on the resolved conifold side, i.e., after the geometric transition, logπ= Vol(CP1) + π
β«
π΅ = πβ is the complexified KΓ€hler parameter which enters the generating function of enumerative invariants.
To summarize, a system of π fivebranes on a knot complement (6.2) is equivalent to a brane configuration (6.4), with a suitable map that relates the boundary conditions in the two cases. There is another system closely related to (6.4) that one can obtain from (6.3) by first reconnectingπ branes onπΏπΎ withπbranes onπ3. This give π branes on ππΎ (that go off to infinity just like πΏπΎ does) plusπ β π branes on π3. Assuming that π βΌπ(1)as π β β(e.g. π=1 in the context of this paper), after the geometric transition we end up with a system like (6.4), except πΏπΎis replaced by ππΎ and Vol(CP1) +π
β«
π΅ =(πβ π)β. Both of these systems on the resolved side compute the HOMFLY-PT polynomials ofπΎ colored by Young diagrams with at mostπrows.
πΉπΎ as the count of open holomorphic curves
From the mathematical point of view, what the above physical picture tells us is that πΉπΎ(π₯ , π, π)is the count of open topological strings in the resolved conifold π, with the knot complement LagrangianππΎ β π.
Mathematically, the large-π transition (going fromπβπ3to the resolved conifold) corresponds to theSymplectic Field Theory (SFT)-stretching[ES19]. With enough stretching, all the curves leave a neighborhood ofπ3, so one can effectively replace πβπ3with the resolved conifold. In order for the SFT-stretching to work nicely, we should be able to shift the Lagrangian completely off of the zero sectionπ3. With ππΎ, that would be exactly whenπΎ is fibered. WhenππΎ is non-fibered, it cannot be completely shifted off of the zero section. Instead, there will be finitely many intersection points whereππΎ looks like the cotangent fiber. In this case, even after SFT-stretching, the curves can end on Reeb chords ending on those intersection points, which complicates the story.
Before moving onto the next topic, let us point out one implication of this interpretation.
Write
πΉπΎ(π₯ , π, π =πππ ) =π
1
ππ ππΎ(π₯ ,π)+π0
πΎ(π₯ ,π)+ππ π1
πΎ(π₯ ,π)+ππ 2π2
πΎ(π₯ ,π)+Β·Β·Β·
.
TheππΎβs are the open Gromov-Witten invariants in our setup (with knot complement LagrangianππΎ). Then, if Λπ is the operator such that
Λ
π :π β¦β π+1 (i.e.,π β¦βπ π), then its expectation value is
β¨πΛβ©|(π¦,π)=(1,1) = lim
πβ1
πΉπΎ(π₯ , π π, π) πΉπΎ(π₯ , π, π)
(π¦,π)=(
1,1)
= ΞπΎ(π₯)β1 (6.5) since, according to Conjecture5.3.2,
πβlim1
πΉπ°π©π
,π π¦ π
πΎ (π₯ , π) = ΞπΎ(π₯)1βπ. But also,
β¨πΛβ©|(π¦,π)=(1,1) =exp
πππΎ(π₯ , π)
πlogπ (π¦,π)=(
1,1)
!
=exp
β« πlogπ¦(π₯ , π)
πlogπ (π¦,π)=(
1,1)
πlogπ₯
!
=exp
β«
β
πlogππ΄πΎ
πlogπ¦π΄πΎ (π¦,π)=(
1,1)
πlogπ₯
! .
So we have a formula forΞπΎ(π₯)in terms of theπ-deformedπ΄-polynomialπ΄πΎ(π₯ , π¦, π). This was confirmed recently by Diogo and Ekholm.
Theorem 6.1.1 ([DE20]). The Alexander polynomial can be computed from the augmentation polynomial3AugπΎ(π₯ , π¦, π)near the abelian branch:
ΞπΎ(π₯)= (1βπ₯)exp
β« π
logπAugπΎ
πlogπ¦AugπΎ
(π¦,π)=(
1,1)
πlogπ₯
! . 6.2 Branches
The variablesπ₯ andπ¦ of the π΄-polynomial correspond to the holonomy eigenvalues of the meridian and longitude of the knot. Since there are always abelianπ πΏ
2(C) connections regardless of the choice of knot, the π΄-polynomial π΄πΎ(π₯ , π¦) always have a factor of (π¦β1). Bybranches, we mean the solutionsπ¦of π΄πΎ(π₯ , π¦) =0 as a function ofπ₯. So, there are as many branches as degπ¦ π΄πΎ(π₯ , π¦). The canonical
3The augmentation polynomial in knot contact homology is essentially the same as theπ-deformed π΄-polynomial (also known as theπ-deformedπ΄-polynomial). See [Aga+14;AV12].
solutionπ¦=1 is called theabelian branch. Similarly in theπ-deformed setting, we call the branch π¦(πΌ)(π₯ , π)abelian branch ifπ¦(πΌ)(π₯ , π =1) =1.
All of our discussions so far have been on the abelian branch. This is because for πΉπΎ(π₯ , π), the expectation value of the Λπ¦operator is always 1:
β¨π¦Λβ©= lim
πβ1
πΉπΎ(ππ₯ , π) πΉπΎ(π₯ , π) =1.
As briefly mentioned in the previous section, a choice of branch corresponds to a choice of vacuum in the 3d theoryπ[ππΎ]. Therefore, it is natural to expect that there are invariants analogous to πΉπΎ(π₯ , π, π) associated to other branches of the π΄-polynomial.
Conjecture 6.2.1([Ekh+22]). Given a knotπΎ, letπ¦(πΌ)(π₯ , π)be a branch ofπ¦near π₯ =0 (orπ₯ =β) of theπ-deformed π΄-polynomial ofπΎ, π΄πΎ(π₯ , π¦, π). Then, there exists a wave functionπΉ(πΌ)
πΎ (π₯ , π, π)associated to this branch in a sense that
β¨π¦Λβ©:= lim
πβ1
πΉ(πΌ)
πΎ (ππ₯ , π, π) πΉ(
πΌ)
πΎ (π₯ , π, π)
= π¦(πΌ)(π₯ , π),
and this wave function is annihilated by the quantum π-deformed π΄-polynomial Λ
π΄πΎ(π₯ ,Λ π¦, π, πΛ )(which is the same for all branchesπ¦(πΌ)(π₯ , π)):
Λ
π΄πΎ(π₯ ,Λ π¦, π, πΛ )πΉ(πΌ)
πΎ (π₯ , π, π) =0.
This conjecture has been checked in numerous examples in [Ekh+22]. In fact, in many cases, we can obtainπΉ(
πΌ)
πΎ (π₯ , π, π)by solving theπ-difference equation given by the quantum π΄-polynomial. If π¦(πΌ)(π₯) βΌπ₯πasymptotically nearπ₯ =0, for some π βQ, then we can use it as the initial condition and find a solution of the form
πΉ(
πΌ)
πΎ (π₯ , π, π) =π
π(log
π₯)2
2 logπ Β· (some Puiseux series inπ₯),
up to an overall factor independent ofπ₯. Possible values ofπ correspond exactly to the boundary slopes of the π΄-polynomial Newton polygon. More precisely,β1
π
should be a boundary slope of the Newton polygon, withπ₯- andπ¦-axis representing theπ₯- andπ¦-degree of the monomials. The abelian branch always corresponds to the slopeβ(or equivalentlyπ =0), and thatβs why the two-variable seriesπΉπΎ(π₯ , π) we considered in previous chapters do not have the exponential prefactorππ
(logπ₯)2 2 logπ
. For non-abelian branches, however,πΉ(
πΌ)
πΎ (π₯ , π)in general involve such a prefactor.
Example 6.2.2 (Figure-eight knot41). For simplicity, letβs consider theπ°π©2 case (i.e., π = π2). The π΄-polynomial of the figure-eight knot is of π¦-degree 3, so it has 3 branches. One of them is the abelian branch, and there are two non-abelian branches of boundary slopeΒ±1
2 which are conjugate to each other. Letβs denote the non-abelian branches byπΌΒ±
1/2, according to their boundary slopes.
Using the quantum π΄-polynomial, we can solve for πΉ
(πΌΒ±
1/2)
41 (π₯ , π)term by term. It turns out, they have nice expressions similar to the inverted Habiro series! Explicitly, they are given by
πΉ
(πΌβ
1/2)
41 (π₯ , π) =π
(logπ₯)2 logπ
βοΈ
πβ₯0
(β1)ππβ
π(πβ1) 2
(π)π
Γ
0β€πβ€π(π₯+π₯β1βππ βπβπ) , and
πΉ
(πΌ1/2)
41 (π₯ , π) =πβ
(logπ₯)2 logπ
βοΈ
πβ₯0
ππ2 (π)π
Γ
0β€πβ€π(π₯+π₯β1βππ βπβπ).
Remark 6.2.3. The abelian branch πΉπΎ(π₯ , π), as we have reviewed extensively in previous chapters, was part of a bigger story that involves closed 3-manifolds. On the other hand, it is not clear at the moment if the non-abelian branchπΉ(πΌ)
πΎ (π₯ , π)βs can be extended to closed 3-manifolds. Given that there seems to be some correlation between the window of good surgery coefficients (Remark4.0.2) and the boundary slope of the π΄-polynomial Newton polygon, it is not too far-fetched to speculate that perhaps these non-abelian branch πΉπΎβs might play some role to get a full understanding of Λπ.
6.3 Holomorphic Lagrangian subvarieties
Consider the Λπoperator that we introduced earlier. It is the operator that substitutesπ byπ π. We have seen that in the abelian branch the expectation value of the Λπoperator provides anπ-deformation of the inverse Alexander polynomial. On other branches π¦(πΌ)(π₯ , π), the expectation value of the Λπ operator will be some other functions; letβs define
π(πΌ)(π₯ , π) := lim
πβ1
πΉ(πΌ)
πΎ (π₯ , π π, π) πΉ(
πΌ)
πΎ (π₯ , π, π) .
It turns out, the functionsπ(πΌ)(π₯ , π)describe branches of the equationπ΅πΎ(π, π, π₯) =0 defined by a polynomialπ΅πΎ(π, π, π₯)that we call theπ΅-polynomialin [Ekh+22]. The π΅-polynomial is uniquely determined by the π΄-polynomial, thanks to the equation
πlogπ(πΌ)(π₯ , π)
πlogπ₯
= πlogπ¦(πΌ)(π₯ , π)
πlogπ .
We summarize theπ΅-polynomials for some simple knots in Table6.1.
πΎ π΅πΎ(π, π, π₯)
01 1βπ
31 1βπ₯β1(2β (1+π₯)π+π₯2π2)π+π₯β2(1βπ) (1βπ₯ π)π2 41
1+πβ1π₯β1(2β (1+3π₯+π₯2)π+2π₯2π2)π
+πβ2π₯β2(1βπ) (1βπ₯ π) (1β2π₯(1+π₯)π+π₯3π2)π2
βπβ2π₯β1(1βπ) (1βπ) (1βπ₯ π) (1βπ₯ π)π3 51
1βπ₯β2 3β2(1+π₯)π+π₯(1+2π₯)π2βπ₯2(1+π₯)π3+π₯4π4 π +π₯β4(1βπ) (1βπ₯ π) (3β (1+π₯)π+2π₯2π2)π2
βπ₯β6(1βπ) (1βπ) (1βπ₯ π) (1βπ₯ π)π3
52
1βπ₯β2
2π2π₯3+π2π₯2β4ππ₯2βππ₯βπ+3π₯+1
π
βπ₯β3(πβ1) (ππ₯β1)
π3π₯4β3π2π₯3β2π2π₯2+5ππ₯2+ππ₯+πβ3π₯β3
π2
βπ₯β4(πβ1)2(ππ₯β1)2
π2π₯3β2ππ₯2βππ₯+π₯+3
π3 +π₯β5(πβ1)3(ππ₯β1)3π4
Table 6.1: Classicalπ΅-polynomials for some simple knots.
One important feature of the π΅-polynomial is that it takes the following simple form in theπ =1 limit, which can be seen from equation (6.5):
π΅πΎ(π =1, π, π₯) =1βΞπΎ(π₯)π .
Theπ΅-polynomial shares many features similar to theπ΄-polynomial. For instance, the π-degree of the π΅-polynomial equals the π¦-degree of the π΄-polynomial (since there is a one-to-one correspondence between the branches). Moreover,π΅πΎ(π, π, π₯=1) always has a factor ofπβ1, just like π΄πΎ(π₯ , π¦, π =1)always has a factor of π¦β1.
Just like π΄-polynomials can be quantized to π-difference equations, so do π΅- polynomials. We summarize the quantumπ΅-polynomials for some simple knots in Table6.2.
In fact, there is a better way to think ofπ΄- andπ΅-polynomials. This is by lifting them to the same holomorphic Lagrangian in(Cβ)4parametrized byπ₯ , π¦, π, π. Physically, this holomorphic Lagrangian corresponds to the Coulomb branch of a 3d-5d coupled system, which should have a quantization. Therefore, we propose the following conjecture.
πΎ π΅ΛπΎ(π,Λ π, π₯ , πΛ )
01 1βπΛ
31 1βπβ1π₯β1(1+πβ (1+ππ₯)πΛ+ππ₯2πΛ2)πΛ+πβ1π₯β2(1βπΛ) (1βππ₯πΛ)πΛ2 41
1+πβ1π₯β1πΛβ1(1+πβ (1+3ππ₯+π2π₯2)πΛ+ππ₯2(1+π)πΛ2)πΛ +πβ2π₯β2πΛβ2(1βπΛ) (1βππ₯πΛ) (1β2ππ₯(1+ππ₯)πΛ+π3π₯3πΛ2)πΛ2
βπβ2π₯β1πΛβ2(1βπΛ) (1βππΛ) (1βππ₯πΛ) (1βπ2π₯πΛ)πΛ3 51
1βπβ2π₯β2 1+π+π2β (1+π) (1+ππ₯)πΛ+ππ₯(1+π₯+ππ₯)πΛ2βππ₯2(1+ππ₯)πΛ3+π2π₯4πΛ4 Λ π +πβ3π₯β4(1βπΛ) (1βππ₯πΛ) (1+π+π2βπ(1+ππ₯)πΛ+π2π₯2(1+π)πΛ2)πΛ2
βπβ3π₯β6(1βπΛ) (1βππΛ) (1βππ₯πΛ) (1βπ2π₯πΛ)πΛ3
Table 6.2: Quantumπ΅-polynomials for some simple knots.
Conjecture 6.3.1([Ekh+22]). Let us endow(Cβ)4with the holomorphic symplectic form
Ξ©:=πlogπ₯β§πlogπ¦+πlogπβ§πlogπ, π₯ , π¦, π, π βCβ.
For every knotπΎ, there is a holomorphic Lagrangian subvarietyΞπΎ β (Cβ)4with the following properties:
1. This holomorphic Lagrangian is preserved under the Weyl symmetry π₯ β¦β πβ1π₯β1, π¦β¦β π¦β1, πβ¦β π, πβ¦β π¦β1π .
2. The projection ofΞπΎon(Cβ)π₯ , π¦,π3 is the zero set of theπ-deformedπ΄-polynomial ofπΎ.
3. Moreover, ifπ₯ ,Λ π¦,Λ π,Λ πΛ are operators such that Λ
π¦π₯Λ=ππ₯Λπ¦,Λ πΛπΛ =ππΛπ,Λ
and all the other pairs commute, then the ideal definingΞπΎ can be quantized to a left idealΞΛπΎ β C[π₯ΛΒ±1,π¦ΛΒ±1,πΛΒ±1,πΛΒ±1]that annihilatesπΉπΎ(π₯ , π, π).
This conjecture can be generalized even further, by introducing theπ‘-variable and its conjugate which we denote byπ’.
Conjecture 6.3.2([Ekh+22]). Let us endow(Cβ)6with the holomorphic symplectic form
Ξ©β²:=πlogπ₯β§πlogπ¦+πlogπβ§πlogπ+πlogπ‘β§πlogπ’, π₯ , π¦, π, π, π‘ , π’ βCβ. For every knotπΎ, there is a holomorphic Lagrangian subvarietyΞβ²πΎ β (Cβ)6with the following properties:
1. This holomorphic Lagrangian is preserved under the Weyl symmetry π₯ β¦β (βπ‘)3πβ1π₯β1, π¦β¦β π‘π π¦β1, π β¦βπ, π β¦β (βπ‘)π 2π¦β1π,
π‘ β¦βπ‘ , π’β¦β π₯βπ π¦β3πβ
π 2π’, whereπ is a version ofπ -invariant of the knotπΎ. 2. The projection ofΞβ²
πΎ on(Cβ)4π₯ , π¦,π,π‘ is the zero set of the super-π΄-polynomial of πΎ.
3. Moreover, ifπ₯ ,Λ π¦,Λ π,Λ π,Λ π‘ ,Λ π’Λare operators such that Λ
π¦π₯Λ =ππ₯Λπ¦,Λ πΛπΛ =ππΛπ,Λ π’Λπ‘Λ=ππ‘Λπ’,Λ and all the other pairs commute, then the ideal definingΞβ²
πΎcan be quantized to a left idealΞΛβ²
πΎ β C[π₯ΛΒ±1,π¦ΛΒ±1,πΛΒ±1,πΛΒ±1,π‘ΛΒ±1,π’ΛΒ±1]that annihilatesπΉπΎ(π₯ , π, π, π‘).4 6.4 Knots-quivers correspondence
In this final section, we briefly review the knots-quivers correspondence for colored HOMFLY-PT polynomials, and then conjecture thatπΉ(
πΌ)
πΎ (π₯ , π, π)also has a quiver form.
Quivers and their representations
A quiver π is an oriented graph, i.e., a pair (π
0, π
1) whereπ
0 is a finite set of vertices andπ
1 is a finite set of arrows between them. We number the vertices by 1,2, ..., π = |π
0|. An adjacency matrix ofπ is theπΓπ integer matrix with entriesπΆπ π equal to the number of arrows fromπto π. IfπΆπ π =πΆπ π, we call the quiver symmetric.
A quiver representation with a dimension vectord= (π
1, ..., ππ)is an assignment of a vector space of dimensionππto the nodeπ βπ
0and a linear mapπΎπ π :Cππ βCππ to each arrow from vertexπto vertex π. Quiver representation theory studies moduli spaces of quiver representations. While explicit expressions for invariants describing those spaces are difficult to find in general, they are quite well understood in the case of symmetric quivers [KS08;KS11;Efi12;MR19;FR18]. Important information about the moduli space of representations of a symmetric quiver is encoded in the
4While we havenβt discussed much aboutπ‘-deformation ofπΉπΎ(π₯ , π, π)in this thesis, since there are quantum super π΄-polynomials that involves both π andπ‘ variables, solving theπ-difference equations we naturally obtain aπ‘-deformation ofπΉπΎ.
motivic generating seriesdefined as ππ(x, π) =βοΈ
dβ₯0
(βπ1/2)dΒ·CΒ·d xd
(π)d = βοΈ
π1,...,ππβ₯0
(βπ1/2)Γπ , ππΆπ πππππ
π
Γ
π=1
π₯ππ
π
(π)ππ
. (6.6)
Let us define theplethystic exponentialof π =Γ
ππππ‘π,π
0=0 in the following way:
Exp π
(π‘) =exp
βοΈ
π 1 ππ(π‘π)
!
=Γ
π
(1βπ‘π)ππ. Then we can write
ππ(x, π) =Exp
Ξ©(x, π) 1βπ
, Ξ©(x, π) =βοΈ
d,π
Ξ©d,π xdππ /2 =βοΈ
d,π
Ξ©(π
1,...,ππ),π
Γ
π
π₯
ππ π
! ππ /2,
(6.7)
whereΞ©d,π are motivic Donaldson-Thomas (DT) invariants [KS08;KS11]. The DT invariants have two geometric interpretations, either as the intersection homology Betti numbers of the moduli space of all semi-simple representations of π of dimension vectord, or as the Chow-Betti numbers of the moduli space of all simple representations ofπof dimension vectord; see [MR19;FR18]. [Efi12] provides a proof of integrality of DT invariants for the symmetric quivers.
Knots-quivers correspondence for knot conormals
In the context of the knots-quivers correspondence, we combineππΎ ,π(π, π) into the HOMFLY-PT generating series:
ππΎ(π¦, π, π) =
β
βοΈ
π=0
π¦βπ (π)π
ππΎ ,π(π, π).
Using this expression we can encode the Labastida-MariΓ±o-Ooguri-Vafa (LMOV) invariants [OV00;LM01;LMV00] in the following way:
ππΎ(π¦, π, π) =Exp
π(π¦, π, π) 1βπ
, π(π¦, π, π) =βοΈ
π ,π, π
ππ ,π, ππ¦βπππ/2ππ/2. (6.8) According to the LMOV conjecture [OV00; LM01; LMV00], ππ ,π, π are integer numbers counting BPS states in the effective 3d N = 2 theories described in subsection6.1.
The knots-quivers correspondence for the knot conormals [Kuc+17; Kuc+19]
is an assignment of a symmetric quiver π (with adjacency matrix πΆ), vector