-There is a potential availability on funded positions in our NSYSU group for MSc students, PhD students, Postdocs (usually filled several months in advance of the following academic year), and short/long term visits. For the MSc and PhD students, a strong theoretical physics background is necessary.
-If you are interested in applying for a long/short term visit, feel free to contact us.
-Joint Postdoc positions with Tsing Hua University and C-S Chu have been announced, you may apply here (these positions have now filled up). 

News:

*** April 16, National Yang Ming Chiao Tung University, Hsinchu, Invited Seminar.

*** April 10, National Taiwan University, Taipei, Invited Colloquium.

*** April 1, New research preprint with our group postdocs M. Afrasiar, J.K. Basak. We propose a holographic formalism for a timelike entanglement entropy in non-conformal theories. This pseudoentropy is a complex-valued measure of information, receives contributions from a set of spacelike surfaces and a finite timelike bulk surface with mirror symmetry, which can merge naturally on the IR tip of our confining spatially compactified geometry. Moreover, we find that the timelike entanglement entropy exhibits unique behavior in confining theories, making it a probe of confinement and phase transitions. In this work we also discuss the entanglement entropy in Euclidean spacetime in confining theories.

*** March 15, New research preprint with A. Kehagias(NTUA), A. Riotto(Geneva U.). Using the Penrose limit on the photon ring we can construct a universal formalism to zoom in and study the photon ring physics. For a large class of axisymmetric black holes we find universally the correspondence of the quasinormal modes of the black hole with the photon ring geodesics.  Additionally we discuss the possibility of photon rings serving as holographic horizons in a holographic duality framework for astrophysical black holes and we propose an upper classical bound on the Lyapunov exponent of the photon ring null geodesics.

*** February 29, National Tsing Hua University, Hsinchu, Invited Seminar.

*** December 26, New research preprint with J. Basak, A. Chakraborty, C-S Chu, and H. Parihar. We introduce new massless Lifshitz scalar field theories using fractional derivatives. We find that their ground state takes the form of Rokhsar-Kivelson. We compute several entanglement measures, which turn out to satisfy the c-function monotonicity along the RG flow. We also introduce for first time the time-like entanglement entropy in Lifshitz theories.

***December 15, "2023 NCTS Annual Theory Meeting: Particle Physics, String Theory, Cosmology, and Astrophysics", Taipei, Invited talk on Quasinormal Modes of Black holes with Penrose limits.

*** November 16, "2023 East Asia Joint Workshop on Fields and Strings", Xian, Invited talk.

*** October 30- November 5, we co-organized the "14th Taiwan String Workshop", in Taipei and Kaohsiung.

*** September 12-19, Coorganized the conference "Quantum Gravity, Strings and the Swampland", Corfu, Greece.

*** August  30, We announce the "14th Taiwan String Workshop", in Taipei and Kaohsiung October 30-November 5.

*** 4 July, The Cyprus Institute, CaSToRC, the HPC National Competence Centre, Cyprus, Invited Seminar.

*** 30 June, New research preprint with J. Basak, S. Mondal, W-Y. Wen. What happens to the multipartite entanglement measures of a quantum state under acceleration or in the presence of gravitational fields? When is the reflected entropy a good measure of correlation and monotonic under partial tracing of degrees of freedom?

*** April 10, We announce the conference "Quantum Gravity, Strings and the Swampland",  September 12-19.

*** 18-24 March, A. Banerjee visited our group and gave a nice interdisciplinary seminar.

*** 8-10 March, Yuki Yokokura from RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), Japan, visited our group and gave a seminar.

*** 17 January, TPS NCTS Theoretical Physics Symposium, NCKU, Tainan, Invited Talk.

*** 16 January, 2022 Young Theory Scholar Award.

***31 December, New preprint on the velocity scaling of observables related to ultrarelativistic motion of bound states in strongly coupled plasmas. The scaling, depends on the asymptotic geometric conditions of the theory, even in cases where the boundary is asymptotically AdS. This also implies that the suppression of heavy mesons in strongly coupled plasmas depends on the direction, and in principle are possible very different and non-continuously related scalings in the suppression.

***22-23 December, "Taiwan String Workshop 2022", Taipei, Invited Talk. 

***19 November, "2022 NCTS Physics Forum and Annual Meeting", Taipei, Taiwan, Invited Talk.

*** 14-18 November, "2022 East Asia Joint Workshop on Fields and Strings", Seoul, Korea,  Invited Talk.

*** 6-12 November, "QCD and Gauge/Gravity Duality", Pohang, Korea, Invited Talk.

*** 11-15 September, "11th Aegen Summer school: Recent developments in Theory and Observations in Gravity and Cosmology", Syros, Invited Talk.

*** 11 September, New preprint on the rotating motion and the renormalization of the heavy quark observables. We introduce the appropriate renormalization schemes in holography for the angular momentum and the energy of rotating heavy  bound states and we explain their implications. We apply our formalism to certain theories by finding the numerical rotating deformed strings solutions and computing their renormalized momenta and energy.

***4-10 September, "Workshop on Holography and the Swampland", Co-Organization with Chatzistavrakidis(RBI), Kehagias(NTUA), D. Lüst(LMU), Rosseel(RBI).

*** 4-10 July, "12th Crete Regional Meeting in String Theory",  Crete, Invited Talk.

*** 28-30 June, "The Future is Illuminating" workshop, Hsinchu.

*** 27 May, National Taiwan University, Taipei, String Theory, Seminar.

*** 23 May, we announce the "Workshop on Holography and the Swampland", we coorganize on Corfu, Greece,  September 4 - 10, 2022.

*** 17 May, National Yang Ming Chiao Tung University, Seminar.

***13 May,  Academia Sinica, High Energy Theory Group, Institute of Physics, Taipei, Seminar. 

*** 5-March, coorganizing NCTS Math-Phys Joint Workshop on Machine Learning, in NTU, Taipei.

*** 7-9 January, "2022 Annual Taiwan Interdisciplinary Theorists Winter Retreat Workshop" in NSYSU, Kaohsiung. Coorganization with H-Y Chen(NTU), C-S Chu(NTHU) and Y-t Huang(NTU).

*** 3 December, New preprint on the chaotic motion of particles near black holes. The Lyapunov coefficient for certain types of motion near the black holes is naturally dependent on the inaffinity on the black hole horizons. With the help of the generalized surface gravity we defined, we argue that in general there is no reason for the Lyapunov exponent of classical trajectories to be bounded in generic spacetimes with horizon. The existence of a bound depends on the particular system.  Moreover,  there is no distinction by the Lyapunov exponent between maximal chaos of black hole and cosmological horizons.

*** 22-27 November, Invited talk for the conference of "East Asia Joint Symposium on Fields and Strings 2021", Osaka, Japan.

*** 17 November, Joint Postdoc positions with Tsing Hua University and Chong-Sun Chu have been announced, you may apply here .

*** 27 October, New preprint on the holography at large dimensions with N. Pappas and N. Toumbas. The large d limit creates a localized potential in the near horizon regime resulting in a simplification of the analysis for the non-local observables, while at the same time retaining their qualitative physical properties. Moreover, the extrapolation to low and intermediate dimensions shows good quantitative agreement with the numerical analysis. The large d limit may be used as a tool for the study and (in)validation of the renormalization group monotonicity theorems.

*** Website Update and migration of the website to the new google sites.

*** 24 December, new research work with N. Tetradis, on the Entropy of Thermal CFTs on Curved Backgrounds. We study properties of thermal CFTs on curved backgrounds that are at a temperature different from that of the cosmological horizon. Our findings are generic and apply to thermal holographic theories with a boundary black hole. 

*** 15 December, NCSR Demokritos Institute of Nuclear and Particle Physics, Greece, Seminar on my recent work.

*** 7 December,  Durham University, UK, Seminar on my recent work.

*** 28 October, Durham University, UK, Colloquium on quark gluon plasma and the theoretical tools to explain this state of matter. 

*** 15 September, our paper with Shotaro Funai Shiba on Machine learning and Renormalization Group on the website of the new Physical Review Research journal followed by a tweet of the APS journal. 

*** 1 September, Editor for the Scipost Proceedings of 4th International Conference on Holography, String Theory and Discrete Approach in Hanoi.

*** 6 August, NTNU, Taiwan. Seminar of my recent work.

*** 5 August,  4th International Conference on Holography, String Theory and Discrete Approach in Hanoi, Invited Speaker.

*** 14 July, New research work on c-functions and phase transitions with M. Baggioli. We propose the c-function as a new way to detect quantum phase transitions with high accuracy.

*** 19 May, University of Crete, Greece, Seminar on my recent work.

*** 17 May, Our "Workshop on New Developments in Quantum Gravity and String Theory" at Corfu, Greece, has been postponed to September 2021.

*** 27 April- 8 May, ”Frontiers of holographic duality", Steklov Mathematical Institute, Moscow, Russia, Online Conference, Invited Talk.

*** 14 April, Public Interdisciplinary Article with Simulations: Deformed Kinetic Theory of Gases as a tool to predict the Epidemic Spreading?

*** 28 February, Our Conference on the Theory of Machine Learning and Theoretical Physics, "Machine Learning for High Energy Physics, on and off the Lattice" at ECT, Trento has been postponed to 21-25 September.

*** 13-18 January and 26 January-3 February, our collaborators K. Zoubos and  JP. Derendinger have visited our group and university.

*** 27 December, NCTS Best Paper Award. Awarded for conducting research on important subjects and carrying out influential works, submitted in 2018 by postdoc researchers at any Taiwanese Institution. 

*** 19-20 December, Co-organizer Athens Xmas Meeting 2019.

*** 7-16 December, CERN Theory Group, Scientific Visit.

*** 26 November, University of Athens, Greece, Seminar.

*** 16-24 November, University of Pretoria, Pretoria, S. Africa, scientific visit.

*** 10-15 November, "Joburg School and Workshop in Theoretical Physics 2019: Aspects of Machine Learning", main lectures and plenary invited research talk, Johannesburg, S. Africa.

*** 10 October, EPFL Innovation Park, and École Polytechnique Fédérale de Lausanne mathematics department, Switzerland, seminar on the applications of theoretical high energy physics on Machine Learning and Artificial Intelligence. Invited by the Private Sector High-Tech Companies.

*** 9 October, Albert Einstein Center for Fundamental Physics, University of Bern, Switzerland, Seminar.

*** 22-25 September "Tenth Aegean Summer School: Recent Developments in theory and observations in gravity and cosmology", plenary invited talk, Syros.

*** 15-22 September, "Tenth Crete Regional Meeting in String Theory", Kolymbari, Talk.

*** 10-15 September,  "Conference on Recent Developments in Strings and Gravity", Invited Talk, EISA, Corfu.

*** 5 September, New results, on the S-matrix Factorization and analytic (non)-integrability. We map features of the 2-dim σ-model spectrum expanded on a non-trivial massive vacuum, to a classical particle Hamiltonian with variable mass. We show that the integrability of the classical particle system, implies the factorization of the S-matrix in the dual quantum 2-dim theory. The equivalence we propose initiates the study of analytic non-integrability techniques on the S-matrix vacua in relation to factorization, and could open new interesting directions of the applicability of those techniques, which go beyond the classification of integrable structures that are mainly used to day.

*** 6-14 August, our collaborator  Da-Shin Lee (Dong-Hwa), have visited our group in Athens. He gave a talk on 8 August, followed by the informal talks by the shorter term group visitor V. Ziogas (Shanghai Jiaotong U.).

*** 21 July, New grant has been received, Durham University, UK.

*** 18 July, Universität Bern, group talk on my recent work. 

*** 4 July, Together with collaborators we have received financial support to organize a workshop in Machine Learning, Theoretical High Energy Physics and Lattice. More details for the upcoming workshop will be out soon.

*** 30 June-3 July, our collaborators A. Athenodorou and K. Zoubos, have visited our group in Athens.

*** 23 June, New work  with C.-S. Chu on the c-functions in anisotropic RG flows. We propose a definition of the c-function in anisotropic theories based on the entanglement entropy. We find the necessary and sufficient conditions for monotonicity along the RG of the c-function for a generic theory. It is possible to impose these conditions only on the boundary UV data of the theory and they will guarantee, for a well defined theory, at least one monotonic c-function along the RG flow. 

*** 21 June, National Taiwan University, Talk on my recent work.

*** 12 June, National Tsing-Hua University, talk on my recent work on Machine Learning.

*** 30 April, New work with N. Tetradis on the entanglement entropy in spaces with horizons. We show that in general the holographic entanglement entropy for the regions enclosed by the horizons, like the de Sitter one, can be identified with the standard thermal entropy by an appropriate redefinition of the effective Newton's constant. 

*** 19 April, "HEP 2019" Conference, NCSR  Demokritos, talk on my recent research.

*** 22 March, Co-organized the "Athens Regional Meeting in Theoretical High Energy Physics", NKUA, Greece.

*** 4 March, University of Ioannina, Talk on my recent research

*** 27 February, National Technical University of Athens, Talk on my recent research.

*** 7-11 January, 8th Bangkok Workshop on High Energy Theory 2019, talk on my recent research.

*** 17-20 December, "NCTS annual meeting 2018: Particles, Cosmology and Strings", plenary invited talk on my research on anisotropic theories and inverse catalysis.

*** 3-17 December, CERN, Theory Group , scientific visit. 

*** 23 November, Rudjer Boskovic Institute, Zagreb, Croatia, videoconference, introductory seminar on applications of gauge/gravity duality. 

*** 22 November, "Director's Seminar", NCTS, Taiwan, seminar on my recent work.

*** 22 October, National Chiao Tung University, Taiwan, talk on my recent work.

*** 19 October, New work on the quick evolving subject of the Machine Learning an its relation to physics appeared. Assuming no prior knowledge of the criticality and the Hamiltonian of a physical system, we find that the machine learning can distinguish physical phase transitions by maximizing certain thermodynamic quantities instead of associating directly the recognition procedure with the RG flow and its fixed points. We also extract the physical critical exponents of the system by Machine Learning!

*** 1-5 October, "10th Joburg School on String Theory", Invited Lecturer, Pretoria, S. Africa.

*** 28 September-12 October, Visit, University of Pretoria and Witwatersrand University, Theoretical Physics Groups, S. Africa. Talk on my recent work.

*** 6-10 August, International Conference on Holography and String Theory, Invited Speaker. Hanoi, Vietnam.

*** 18-27 July, Formosa Summer School on High Energy Physics, and Scientific Visit in National Dong-Hwa University, Taiwan. 

*** 25 June-3 July, Strings 2018 and Scientific Visit, OIST, Okinawa, Japan.

*** 8 June, Academia Sinica, Review Talk on my Research and on Applications of Gauge/Gravity duality to the Strongly Coupled Systems.

*** 27 May - 2 June, National Dong-Hwa University, Scientific Visit. Delivered undergraduate review lectures on Special Relativity.

*** 23 May, New review appeared. In holography we develop a theory-independent approach to study the stochastic motion of the heavy quarks. Several formulas like the Langevin coefficients can be written in such a way to be directly applicable to any holographic theory. In a similar way, the Brownian motion analysis can be studied in such a way to accommodate a wide class of theories.

*** 21 May, New research work appeared. Holographic baryons under strong magnetic fields or in other anisotropic theories have very interesting properties. For example, the baryons dissociate in stages, and the pairs of quarks which abandon the state easier as the temperature of the heat bath increases, depend on their proximity to the magnetic field direction.

*** 24 April, University of Ioannina. Seminar on my recent work!

*** 29 March, ''HEP 2018, Recent Developments in High Energy Physics and Cosmology'' Conference, NTUA, Athens. Talk on my recent work.

*** 14 February. Motivated by the wide range of applicability of the fluctuation and dissipation phenomena in non-equilibrium systems, we provide a universal study scheme for quantum fluctuation and dissipation in strongly coupled theories.  A new work with D-S Lee and C-P Yeh.

*** 24-26 January, "Annual Meeting of the Physical Society of Taiwan, (TPS)", NTU. Talk on my recent work.

*** 19-24 January, National Dong-Hwa University, Scientific Visit.

*** 17-23 December, Asia Pacific Center for Theoretical Physics, (APCTP), Korea. Scientific Visit and Talk on my recent works.

*** 5-8 December, "NCTS Annual Theory Meeting 2017: Particles, Cosmology and Strings", Taiwan. Talk on my recent work.

*** 13-17 November,  "2nd East Asia Joint Workshop on Fields and Strings", KEK Tsukuba, Japan. Talk on my recent work.

*** 9-12 November, "Workshop on recent developments in QCD and quantum field theories". Talk on my recent works on applications of AdS/CFT.

*** 26-29 October, "10th Taiwan String workshop''. Talk on my recent work, on chaos in string theory.

*** 23-25 October, ''Joint Workshop on issues on Perturbation from inflation'', (General Relativity and Quantum Cosmology, (gr-qc) oriented), talk on relevant supergravity solutions.  

*** 1-5 October, Visit, Okinawa Institute of Science and Technology, OIST, Japan. Talk on my recent work.

*** 4 September, Talk, "Standard model and beyond conference" (mostly hep-ph, hep-ex oriented), EISA Corfu.

*** 18 August, New Preprint with U. Gursoy and J. Pedraza. Strongly coupled theories with anisotropies(i.e. in strong fields), have lower confinement-deconfinement critical temperature. This is true even for neutral plasmas, suggesting that the anisotropy by itself is the main cause for the inverse magnetic catalysis.

*** 23-25 July, Visit National Dong Hwa University. Talk on my recent work.

*** 8-19 July,  Visit, University of Bern, Albert Einstein Center for Fundamental Physics, Switzerland.

*** 13 July, New preprint with K. Zoubos. In integrable theories, when the quark loops are taken into account they become non-integrable and chaos occurs. There exist certain saturation effects on chaos when the number of flavors approach the number of colors.

*** 17 May, Chung-Yuan University, Theoretical physics group. Talk on my recent work.

*** 19 April-May 2, Visit, University of Pretoria and Witwatersrand University, Theoretical Physics Groups, S. Africa. Talk on my recent work.

*** 6-9 April, HEP 2017, Conference on Recent Developments in High Energy Physics and Cosmology, Ioannina, Greece, plenary talk on my recent work.

*** 13 March, NCTS Mini-Workshop on High Energy Physics, talk on my recent work. 

*** 16 January, Leung Center for Cosmology and Particle Astrophysics (LeCosPA),  talk on my recent work.

*** 23 December, International workshop "Holography for NICA", Steklov Mathematical Institute of Russian Academy of Sciences, Moscow, Russia. Videoconference Invited Talk on my work.

*** 13 December, National Chiao Tung University, Taiwan, talk on my recent work.

*** 6-9 December, NCTS Annual Theory Meeting, Taiwan, talk on my recent work.

*** 26 August, New preprint with Chong-Sun Chu. Observables in an expanding strongly coupled de Sitter universe feel a thermal bath, which shares similarities with the finite temperature strongly coupled field theories in flat space.

*** 22-29 August, Holography and Topology of Quantum Matter Workshop, APCTP, Korea. Invited talk on my recent work.

*** 23 August. New preprint with Feng-Li Lin and Pei-Hua Liu. A model for holographic quantum energy teleportation is proposed using the surface/state duality.

*** 25-29 July, NCTS Summer Workshop, Hsinchu, Taiwan, talk on my recent work.

*** 10-16 July, Pascos 2016 International Symposium, Quy Nhon, Vietnam, talk on my recent work. 

*** 1st July, National Taiwan University, talk on my recent work.

*** 19 May, National Taiwan Normal University, Taipei, Taiwan, talk on my recent work.

*** 19 April, New preprint with Chong-Sun Chu. A general formalism for the two-point functions in CFT has been developed and applied to the AdS space with a dS slicing as a boundary.

*** 15 March, National Chiao Tung University, Hsicnhu, Taiwan, talk on my recent work.

*** 30 January-4 February, "3rd KIAS-NCTS Joint Workshop",High1, Korea, talk on my recent work.

*** 17-21 January, Visit, University of Cyprus, Nicosia, Cyprus, and talk on my recent work.

*** 15 January, Co-Organizing for second time the HEP Athens Regional Meeting, Athens, Greece. 

*** 27-30 December, Visit, APCTP, Pohang, Korea, and talk on my recent work. 

*** 16 December, NCU, High Energy Theory group, Taiwan. Talk on my recent work.

*** 9-12 December, NCTS Annual Theory Meeting, talk on my recent work.

*** 4 December, National Taiwan University, talk on my recent work.

*** 16-20 November, 8th Taiwan String Workshop, talk on my recent work.

*** 28 October, NCTS, talk on my recent work. 

*** 1st October, Research Scholar in National Center for Theoretical Physics (NCTS).

*** 14-25 September, Visit,  University of Barcelona, Theoretical Physics Group, Spain.

*** 25 July-12 August, Visit, University of Pretoria and Witwatersrand University, Theoretical Physics Groups, S. Africa. Colloquium given, and two talks on my recent work.

*** 12-23 July, Visit, University of Bern, Albert Einstein Center for Fundamental Physics, Switzerland.

*** 14 June-9 July, Visit, University of Barcelona Theoretical Physics Group, Spain.

***** New External Research Grant offered, ~90 K Euros, with University of Barcelona.

*** 26 May, New short review written. It is on the properties of confinement in holography and few recent developments.

*** 5-9 May, Visit, Universidad de Santiago de Compostela theory group, Spain. Talk on my recent work.

*** 19 April-5 May, Visit, University of Oviedo Hep-th group, Spain. Talk on my recent work.

*** 15-18 April, Hep 2015 Conference, Athens. Talk on my recent work.

*** 31 March, New preprint. In particular large N SU(N) gauge theories, the k-quark bound states can be treated as a single meson state with different string tension.

***  23-24 March, Visit University of Swansea and Talk on my recent work. 

***  9 March, Talk, Oxford University on my recent work.

*** 17 February, New preprint with N. Irges. The flux tubes between the heavy Quark-antiQuark bound state, have logarithmic broadening in any confining gauge/gravity duality.

*** 11-13 February, Visit, University of Barcelona and talk on my recent work.

*** 18 November, New preprint with K.Goldstein. In the low temperature confining phase, the string tension in the linear static potential of a heavy quark bound state reduces with the temperature.

*** 1st October, Visiting Fellowship, Holography Group, Oxford University.

*** 22-26 September, The String theory Universe, 20th European Workshop on String Theory, Mainz, Germany.  Talk on my recent works.

*** 14-21 September, Corfu 2014, String Theory workshop, Hellas. Talk on my recent works.

***  22 July, Talk in NTUA, about some recent and on-going work on the range of certain universality relations in AdS/CFT.

***  6-18 July, Visiting the CERN hep-th group.

*** 10 June, New preprint. The heavy quarkonia moving in the QGP dissociate easier than the static ones, taking into account the contributions of screening and also Landau damping phenomena.

*** 3 June, Talk in University of Athens about the Gauge/gravity dualities and the QGP.

*** 25-30 May, Visiting University of Mons and a talk in Brussels cental seminar about some of my recent works in anisotropic Quark Gluon Plasmas.