1. June 25, 2015 ICTS-TIFR Bengaluru, India Strings 2015

2. MAIN MESSAGES  Black hole microstates involve complicated structure of branes called superstrata  Basic superstrata solutions explicitly constructed in sugra as smooth geometries

3. Iosif Bena Jan de Boer Nick Warner Stefano Giusto Rodolfo Russo

4. MICROSTATE GEOMETRY PROGRAM: How much of black hole entropy can be accounted for by smooth, horizonless solutions of classical gravity? no horizon, no singularity

5. 1915Einstein: general relativity 1975Hawking radiation 1996Strominger-Vafa (field theory counting of 3-charge BH) 2001Lunin-Mathur geometries (2-charge microstates)  fuzzball conjecture, microstate geometry program 2006Microstate geometries in 5D (3- and 4-charge microstates) 2010Double bubbling & superstrata (into 6D) 2015Explicit construction of superstrata SOME HISTORY This talk

6. DOUBLE BUBBLING (OR MULTIPLE SUPERTUBE TRANSITION)

7. SUPERTUBE TRANSITION  Spontaneous polarization phenomenon  Produces new dipole charge  Cross section = arbitrary curve [Mateos+Townsend ’01] 7 new dipole charge polarize (“bubble”) arbitrary curve (cf. Myers effect)

8. SUPERTUBE: F1-P FRAME F1(9) polarize P wiggly F1 8 compact transverse

9. SUPERTUBE: D1-D5 FRAME D5D1 polarize (“bubble”) KKM arbitrary curve 9 [Lunin-Mathur ’01] [Rychkov ’05] [Lunin-Mathur ’01] [Kanitscheider-Skenderis-Taylor ’06, 07]

10. DOUBLE BUBBLING D5D1 P arbitrary curve: supertube arbitrary surface: “superstratum” 3-charge system: real BH [de Boer-MS ’10, ’12] [Bena-de Boer-MS-Warner ’11] 10

11. ENDLESS BUBBLING? A black hole is made of an extremely complicated structure (fuzzball) of puffed-up branes. 7 ? Courtesy of the National Human Genome Research Institute

12. 12 EXOTIC BRANES exotic brane U-duality monodromy  “Forgotten” branes in string theory  Codimension 2  U-duality monodromy (“U-fold”)  Non-geometric [de Boer-MS ’10, ’12] [Elitzur-Giveon-Kutasov-Rabinovici ’97] [Blau-O’Loughlin ’97] [Hull ’97] [Obers-Pioline ’98] generalization of F-theory 7-branes

13. A GEOMETRIC CHANNEL wiggly KKM wiggly D1 wiggly D5 D1D5 P geometric superstratum = 13 [Bena-de Boer -MS-Warner ’11]

14. SUMMARY:  BH microstates involve double-bubbled superstrata  Geometric superstratum in 6D is important for microstate geometry program

15. EXPLICIT CONSTUCTION OF SUPERSTRATA [Bena+Giusto+Russo+MS+Warner ’15]

16. GOAL: Explicitly construct “superstrata” = wiggly KKM in 6D

17. SUSY SOLUTIONS IN 6D 17 [Gutowski+Martelli+Reall ’03] [Cariglia+Mac Conamhna ’04] [Bena+Giusto+MS+Warner ’11] [Giusto+Martucci+Petrini+Russo ’13]

18. BPS EQUATIONS 18 1 st layer 2 nd layer Give 4D base 0 th layer Linear if solved in the right order

19. 0 TH LAYER 19 Give 4D base  This is the base for: round LM geometry (2-charge) round superstratum with no wiggle (yet)

20. 1 ST LAYER 20 Give 4D base [Mathur+Saxena+Srivastava ’03]  Mode numbers: (,)  Take known linear solution with P

21. 1 ST LAYER (2) 21 Give 4D base  Superpose modes to get function of 2 variables

22. NL completion 2 ND LAYER 22 Give 4D base

23. SUMMARY:  Constructive proof of existence of superstrata!  Big step toward general 3-charge microstate geometries  Most general microstate geometry with known CFT dual

24. CFT PICTURE

25. 25 BOUNDARY CFT  Orbifold CFT  Twist sectors represented by component strings ………

26. 26 2-CHARGE STATES (1)  Round LM geom

27. 27 2-CHARGE STATES (2)  General LM geom  Linear fluct around round LM ……… [Lunin-Mathur ’01]

28. 28 KNOWN 3-CHARGE STATES  P-carrying linear fluct around round LM ……… “known linear solution” [Mathur+Saxena+Srivastava ’03]

29. 29 SUPERSTRATA  General P-carrying fluct around round LM ……… ………

30. TOWARD MORE GENERAL STRATA

31. 31 WHAT’S MISSING  Not yet  [de Boer ’98]

32. MORE GENERAL SUPERSTRATA 32 multi- superstratum Next steps:

33. CONCLUSIONS

34. CONCLUSIONS:

35. STAY TUNED

36. Thanks!