Computational topology of con guration spaces - ICERM · Computational topology of con guration...

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Computational topology ofconfiguration spaces

Yoav Kallus

Santa Fe Institute

Stochastic Topology and Thermodynamic LimitsICERM, ProvidenceOctober 17, 2016

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 1 / 18

Clustering of the phase space

φVolume fraction,

Pre

ssure

, P

φ φ φth K GCPd

φ

Σ

j

φ

Σequilibrium

snon−planted−clusters

planted−clusters

stot

CsCd CcAverage degree

14

13.6 13.4 13.2 13 12.8 12.6

0.2

0.15

0.1

0.05

0 13.8

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 2 / 18

Clustering of the phase space

φVolume fraction,

Pre

ssure

, P

φ φ φth K GCPd

φ

Σ

j

φ

Σequilibrium

snon−planted−clusters

planted−clusters

stot

CsCd CcAverage degree

14

13.6 13.4 13.2 13 12.8 12.6

0.2

0.15

0.1

0.05

0 13.8

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 2 / 18

Clustering of the phase space

φVolume fraction,

Pre

ssure

, P

φ φ φth K GCPd

φ

Σ

j

φ

Σequilibrium

snon−planted−clusters

planted−clusters

stot

CsCd CcAverage degree

14

13.6 13.4 13.2 13 12.8 12.6

0.2

0.15

0.1

0.05

0 13.8

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 2 / 18

k-SAT clustering

Theoremβ, γ, θ, δ and εk → 0 exist such that for a random k-SATformula with n variables and m = αn clauses, where

(1 + εk)2k log(k)/k ≤ α ≤ (1− εk)2k log(2)

the solution can is partitioned w.h.p. into clusters, s.t.

there are ≥ exp(βn) clusters,

any cluster has ≤ exp(−γn) of all solutions,

solutions in distinct clusters are ≥ δn apart, and

any connecting path violates ≥ θn clauses along it.

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 3 / 18

Moore & Mertens, The Nature of Computation

Clustering phenomenology

All about connected components of the configurationspace. What about higher dimensional topologicalinvariants?

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 4 / 18

Moore & Mertens, The Nature of Computation

Clustering phenomenology

All about connected components of the configurationspace. What about higher dimensional topologicalinvariants?

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 4 / 18

Moore & Mertens, The Nature of Computation

5 disks in a square

0.1000

0.1464 0.1306 0.12500.1667

0.1686 0.1686 0.14790.16020.1667 0.16670.1681

0.17050.1942 0.16920.1871 0.1693

0.2071 0.1964 0.1705

1

2

3

4

5

6

2

2

2

3

3

3

4

4 4

4 4

4 4

5

5 5

6

6

6 6

6

6 6

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 5 / 18

Carlsson, Gorham, Kahle, & Mason, Phys. Rev. E 85, 011303 (2012)

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 6 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 6 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 6 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 6 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 6 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 6 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 7 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 7 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 7 / 18

The perceptron

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 7 / 18

The perceptron – Betti numbers

0

5

10

15

20

25

n = 6

0

10

20

30

40

50

60

70

n = 7

0.0 0.2 0.4 0.6 0.8 1.01/R^2

0

50

100

150

200

n = 8

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 8 / 18

The perceptron – persistence homology

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 9 / 18

Stochastic topology, a different criticality

d fixed, n→∞: structure only at local scaled , n→∞, d ∼ exp(n2): no spatial structured , n→∞, d ∼ n: structure at all scales

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 10 / 18

Stochastic topology, a different criticality

d fixed, n→∞: structure only at local scaled , n→∞, d ∼ exp(n2): no spatial structured , n→∞, d ∼ n: structure at all scales

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 10 / 18

The sphere packing problem

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 11 / 18

log2 δ + 196n(24 − n)

Conway & Sloane, SPLAG

Packing problem restricted to lattices

Restricted to lattices, what is the densest packingstructure?

n L2 A2 Lagrange (1773)3 D3 = A3 Gauss (1840)4 D4 Korkin & Zolotarev (1877)5 D5 Korkin & Zolotarev (1877)6 E6 Blichfeldt (1935)7 E7 Blichfeldt (1935)8 E8 Blichfeldt (1935)

24 Λ24 Cohn & Kumar (2004)

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 12 / 18

The space of latticesL = AZn

, so L =

O(n)\

GLn(R)

/GLn(Z)

But AZn and RAZn are isometric if R is a rotation.But AZn and AQZn are the same lattice if QZn = Zn.

O(n)\GLn(R) = Sn>0 ⊂ Symn, the space of symmetric,positive definite matrices: take G = ATA.

Symn

Sn>0

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 13 / 18

The space of latticesL = AZn, so L =

O(n)\

GLn(R)

/GLn(Z)But AZn and RAZn are isometric if R is a rotation.But AZn and AQZn are the same lattice if QZn = Zn.

O(n)\GLn(R) = Sn>0 ⊂ Symn, the space of symmetric,positive definite matrices: take G = ATA.

Symn

Sn>0

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 13 / 18

The space of latticesL = AZn, so L =

O(n)\

GLn(R)

/GLn(Z)

But AZn and RAZn are isometric if R is a rotation.

But AZn and AQZn are the same lattice if QZn = Zn.

O(n)\GLn(R) = Sn>0 ⊂ Symn, the space of symmetric,positive definite matrices: take G = ATA.

Symn

Sn>0

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 13 / 18

The space of latticesL = AZn, so L =O(n)\GLn(R)

/GLn(Z)

But AZn and RAZn are isometric if R is a rotation.

But AZn and AQZn are the same lattice if QZn = Zn.

O(n)\GLn(R) = Sn>0 ⊂ Symn, the space of symmetric,positive definite matrices: take G = ATA.

Symn

Sn>0

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 13 / 18

The space of latticesL = AZn, so L =O(n)\GLn(R)/GLn(Z)But AZn and RAZn are isometric if R is a rotation.But AZn and AQZn are the same lattice if QZn = Zn.

O(n)\GLn(R) = Sn>0 ⊂ Symn, the space of symmetric,positive definite matrices: take G = ATA.

Symn

Sn>0

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 13 / 18

The space of latticesL = AZn, so L =O(n)\GLn(R)/GLn(Z)But AZn and RAZn are isometric if R is a rotation.But AZn and AQZn are the same lattice if QZn = Zn.

O(n)\GLn(R) = Sn>0 ⊂ Symn, the space of symmetric,positive definite matrices: take G = ATA.

Symn

Sn>0

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 13 / 18

The Ryshkov polyhedronWe are interested in the lattices with packing radius ≥ 1:{G ∈ Sn>0 : n · Gn ≥ 1 for all n ∈ Zn}.

n1 ·Gn1 ≥ 0

Sn>0

Symn

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 14 / 18

The Ryshkov polyhedronWe are interested in the lattices with packing radius ≥ 1:{G ∈ Sn>0 : n · Gn ≥ 1 for all n ∈ Zn}.

Symn

Sn>0

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 14 / 18

The Ryshkov polyhedronWe are interested in the lattices with packing radius ≥ 1:{G ∈ Sn>0 : n · Gn ≥ 1 for all n ∈ Zn}.

Symn

Sn>0

R

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 14 / 18

The Ryshkov polyhedronThe polytope is locally finite, and has finitely many facesmodulo GLn(Z) action

Symn

Sn>0

R

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 14 / 18

The Ryshkov polyhedronWe determinant (equivalently, density) gives a filtrationof the space

Symn

Sn>0

R

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 14 / 18

Lattice RCP

2 5 10 20 50

101

102

103

slope = 1

slope = 2.61

d

2dϕ

0.85 0.9 0.95 1 1.05 1.1 1.15

0

10

20

30

0

ϕ/〈ϕ〉

〈ϕ〉P

(ϕ)

15161718192021222324

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 15 / 18

K, Marcotte, & Torquato, Phys. Rev. E 88, 062151 (2013)

Pair correlations and quasicontacts

1 1.2 1.4 1.6 1.8

0.9

1

1.1

1

r

g(r)

15 16 1718 19 2021 22 2324

10−4 10−3

10−1

100

r − 1(r

−1)(dZ

/dr)

15 16 1718 19 2021 22 2324

g(r) ∼ (r − 1)−γ

Z (r) ∼ d(d + 1) + Ad(r − 1)1−γ

γ = 0.314± 0.004

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 16 / 18

K, Marcotte, & Torquato, Phys. Rev. E 88, 062151 (2013)

Contact force distribution

0 0.5 1 1.5 2 2.5 3 3.50

0.2

0.4

0.6

f/〈f〉

P(f

/〈f

〉)

15161718192021222324

2.5 3 3.5 410−4

10−3

10−2

10−1

10−3 10−2 10−1

10−5

10−4

10−3

10−2

10−1

f/〈f〉(f

/〈f

〉)P(f

/〈f

〉)

P(f ) ∼ f θ

θ = 0.371± 0.010

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 17 / 18

K, Marcotte, & Torquato, Phys. Rev. E 88, 062151 (2013)

Topology of the space of lattices

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 18 / 18

Elbaz-Vincent, Gangl, & Soule, Perfect forms and the cohomology of modulargroups, arXiv:1001.0789

The perceptron – persistence homology

Y. Kallus (Santa Fe Institute) Configuration space topology ICERM, Oct. 17, 2016 19 / 18