# Journal Club

The Journal Club is a series of student led talks and discussions that happen every week in the ACC 211 conference room. UC folks can sign up for the mailing list here.

### WINTER 2017

Topic: Topological Quantum Field Theories.

Meeting time: Thursday 1:30 PM

1.Jan 12th, arXiv: 1606.01989 continued

2. Jan 19th, application of duality: nu = 1/2 state in quantum Hall physics

3. Jan 26th, E. Witten, *Topological Quantum Field Theory*, Commun. Math. Phys. **117**, 353 (1988) I

4. Feb 2nd, E. Witten, *Topological Quantum Field Theory*, Commun. Math. Phys. **117**, 353 (1988) II

5. Feb 9th, X.-L. Qi, E. Witten, and S.-C. Zhang, *Axion Topological Field Theory of Topological Superconductors*, Phys. Rev. B. **87**, 134519 (2013)

6. Feb 16th, E. Witten, *Quantum Field Theory and the Jones Polynomial*, Commun. Math. Phys. **121**, 351 (1989) I

7. Feb 23rd, E. Witten, *Quantum Field Theory and the Jones Polynomial*, Commun. Math. Phys. **121**, 351 (1989) II

8. Mar 2nd, K-Matrix Formulation of Quantum Hall physics mainly based on works by X.-G. Wen

9. Mar 9th, E. Witten, *2+1 Dimensional Gravity as an Exactly Soluble System*, Nucl. Phys. B **311**, 46 (1988)

### FALL 2016

Topic: Duality in condensed matter physics and Composite Fermions.

Meeting time: Thursday 1:30 PM

1. Ising model 1 (Introduction) (Tan)

Suggested reference:

- Feynmann’s lectures on Statistical Mechanic

- Review of Modern physics reviews here and here

- Fradkin’s book

2. Ising model 2 (Duality of Ising model) (Bogatskii)

Suggested reference:

- High T low T duality (Kramers-Wannier)

- Boson-fermion duality in 1+1 related to Ising model (Polchinski’s String theory books, CFT book http://www.springer.com/us/book/9780387947853, Emil’s lecture note )

- Sine-Goron duality here and here

3. Bosonization (Chang)

Suggested reference:

- Lecture by Kane about bosonization and references

- Bosonization for Fermi-liquid (Castro Nesto and Fradkin, Haldane)

4. Bosonic particle/vortex duality (MacCormack)

Suggested reference:

PRL's here and here, and a good review

- Karch and Tong Partilce/Vortex Duality https://arxiv.org/abs/1606.01893

5. S-duality (electric-magnetic duality) (Chris)

Suggested reference:

- T-Duality Polchinski’s books on String theory

- 4D- Maxwell theory lecture note by Jeff https://arxiv.org/abs/hep-th/9603086

6. Witten’s paper on duality 1 (Harvey)

Suggested reference:

- Karch and Tong paper on the same topic

7. Witten’s paper on duality 2 (Travis or Joao)

Suggested reference:

8. Witten’s paper on duality 3 (Travis or Joao)

Suggested reference:

9. ½ state and particle vortex duality (Dung)

Suggested reference:

PR X paper and review paper by Son

### SPRING 2016

Topic: Scattering Amplitudes. We will be covering the book by Elvang and Huang, *"Scattering Amplitudes in Gauge theory and Gravity"*. Meeting time: Thursday 1:00 PM

Week 1 (Apr 21) Yu-Xiao Wu Chapter 2&3 of the book

Week 2 (Apr 28) João Caldeira Chapter 2&3 of the book

Week 3 (May 05) Yi-Kun Wang Chapter 2&3 of the book

Week 4 (May 12) Jing-Yuan Chen Chapter 6&7&8 of the book, can skip N=4 SYM

Week 5 (May 19) Wei-Han Hsiao Chapter 6&7&8 of the book, can skip N=4 SYM

Week 6 (May 26) * Special: We are happy to have Jaroslav Trnka, who will present a review of the subject. On the same week he will give another seminar about his own research.

Week 7 (June 02) Travis Maxfield Twistor and recent extensions 1412.3479

Week 8 (June 09) Caner Nazaroglu Twistor and recent extensions 1412.3479

### Winter 2016

Topic: Quantum Information in AdS/CFT. Meeting time: Tuesday 12:30 PM

1. 01/19 Introduction to Quantum Computation – Dung Nguyen

2. 01/26 Classical Information Theory/Von Neumann Entropy/Entropy Inequalities – Caner Nazaroglu

3. 02/02 Quantum Error Correction – Jingyuan Chen

4. 02/09 Introduction to AdS/CFT – Franklin Wu

5. 02/16 Ryu Takayanagi - Travis Maxfield

6. 02/23 QFT In Curved Spacetimes – Michael Geracie

8. 03/01 Emergent Spacetime – Chris Heinrich

9. 03/08 Tensor Networks – Wei Han

7. 03/15 Tensor Networks and Holography – Joao Caldeira

10. 03/29 Holographic Quantum Error Correcting Codes – Michael Geracie

### Spring 2015

This quarter students will present a topic relevant to their own research. Meetings will be held weekly at 1:30 PM on Thursdays with the first talk on 4/16/15.

1. Caner – Conformal Bootstrap

2. Chris – SPT phases

3. Jingyuan – Chiral Kinetic Theory

4. Tommy – SCFT and Elliptic Genus

5. Hridesh – Knotted Light

6. Franklin

7. Travis

8. Chien-Hung

### Winter 2015

This quarter we will be covering the phases of QCD and symmetry protected topological (SPT) Phases. Talks will be held each week at 12:00 Thursday.

QCD:

1. Perturbative QCD at high T (Gross, Pisarski, Yaffe 1981) – Alex

2. Polyakov loops and deconfinement – (Polyakov 1976, Svetitsky, Yaffe 1982) – Joao

3. Chiral phase transitions (Pisarski, Wilczek 1984) – Travis

4. Color superconductivity (Alford, Rajagopal, Wilczek 1998/1999, Alford, Schmitt, Rajagopal, Schafer 2008) – Mike

5. QCD Critical Point (Sthephanov, Rajagopal, Shuryak 1999, Stephanov 2004) - Jingyuan

SPT:

1. 1D spin models: Haldane spin chain and generalizations – Misha

2. Group cohomological classification in 1D – Dung

3. Analyzing bulk statistics in 2D – Chris

4. Analyzing edge states in 2D – Chien-Hung

### Fall 2014

This quarter’s journal club is concerned with anomalies and their applications. Please see Professor Harvey’s 2003 TASI lectures for a good source of references. The topics covered this quarter are

1. Introduction/Motivation/Phenomenology - Jeff Harvey

2. Spectral Flow and 1 Loop Amplitudes - Michael

3. Fujikawa path-integral analysis - Chris

4. Anomalies and transport (chiral magnetic and vortical effect) - Siavash

5. Anomaly inflow - João

6. Descent Equations - Jingyuan

7. Index Theory - Franklin

8. Anomaly matching / Examples - Caner

9. Conformal Anomaly - Travis

### Spring 2014

Week 1: Entanglement Entropy - Density Matrix Renormalization Group

Week 2: Entanglement Entropy - Multiscale Entanglement Renormalization Ansatz (Vidal)

Week 3: Anyonic Physics - Introduction to Chern Simons (Witten)

Week 4: Anyonic Physics - Introduction to Chern Simons -- Knot/Link Invariants

Week 5: Anyonic Physics - Wilson lines/non-local operators/ Laughlin Wavefunction

Week 6: Anyonic Physics - Algebraic Theory of Anyons (Preskill Lecture Notes)

Week 7: Anyonic Physics - Algebraic Theory of Anyons (Preskill Lecture Notes)

Week 8: Anyonic Physics - Edge States Theory

Week 9: Anyonic Physics - Edge States Experiment

### Winter 2014

This quarter's series is mostly concerned with a pedagogical introduction to the subject of quantum entanglement; the discussion may spill over into the next quarter. A summary with refereances is the set of lectures by Takayanagi. A collection of review articles from 2009 may be found here.

1. Intro to Entanglement Entropy. Finite dimensional systems, spin chains. Von-Neumann entropy and its properties (e.g. Strong subadditivity, inequalities etc.), mutual information, relative entropy, etc.

2. Area law of entanglement entropy. Srednicki (hep-th/9303048)

3. Review of CFT, Anomalies, Boundary CFT, C/g theorems.

4, 5. Entanglement entropy in 2D CFTs (first lecture and continuation into a second lecture) (Callan-Wilczek, Calabrese-Cardy, Kitaev, Calabrese-Cardy review)

6. Non-equil dynamics of EE Quench, time development (Calabrese-Cardy, Bernard-Bauer)

7. Topological EE (Kitaev-Preskill, Levin-Wen, Ludwig et. al)

8. Intro to holography and Holographic EE (Ryu-Takayanagi)

9. Black holes and Entanglement CFT thermal field duals and AdS Blackholes (Maldacena)

10. Entanglement and Hawking radiation (aka information paradox and firewalls)

11. Relation between topological EE and edge states (Entanglement spectrum)

12. Entanglement renormalization MERA (Multiscale Entanglement Renormalization Ansatz; Vidal), Swingle, DMRG (density matrix RG) + Numerics

### Fall 2013

This quarter's series is mostly concerned with a pedagogical introduction to the subject of topological states of matter. We are mostly follow the ordering of the topics in the short review of

Hasan and Kane, Rev. Mod. Phys. 82, 3045 (2010).

0. Review of band structure and the tight binding method.

1. Integer quantum Hall effect

Physical picture of gap, edge states, Hall conductivity

2. TKNN paper: connection between sigma_xy and Chern number

Refs: Thouless et al. PRL 49, 405 (1982)

Haldane PRL 61, 2015 (1988).

3. High-energy perspective

Jackiw and Rebbi, Phys. Rev. D 13, 3398 (1976).

Nielsen and Ninomiya, Phys Lett 130B, 389 (1983)

4. Z2 topological insulator

Kane and Mele PRL 95, 226801 (2005)

explain Eqs. (11), (12) of the review. Explain Eq.(10) of the review

5. Proposal for topological insulator and experiments

Benevig, Hughes and Zhang, Science 314, 1757 (2006).

Koenig et al, Science 318, 766 (2007).

6. 3D toplogical insulator

strong and weak TI

weak TI as a stack of 2D TI

surface modes

Ref: Fu, Kane and Mele, PRL 98, 106803 (2007).

7 Experiments with 3D TIs

Hsieh et al., Nature 452, 970 (2008)

The review itself

8. Axion electrodynamics

Refs: Wilczek PRL 58, 1799 (1987)

Essin, Moore and Vanderbilt, PRL 102, 146805 (2009)

Qi, Hughes and Zhang, Phys. Rev. B 9, 195424 (2008)

9a. Periodic table

Refs.: Stone, Chiu and Roy, arXiv:1005.3213

Kitaev http://arxiv.org/abs/0901.2686

9b. Topological superconductors