Physics
http://repository.iitgn.ac.in/handle/123456789/607
2018-03-17T10:30:20ZA new constant-size accountable ring signature scheme without random oracles
http://repository.iitgn.ac.in/handle/123456789/3530
A new constant-size accountable ring signature scheme without random oracles
Kumawat, Sudhakar; Paul, Souradyuti
Accountable ring signature (ARS), introduced by Xu and Yung (CARDIS 2004), combines many useful properties of ring and group signatures. In particular, the signer in an ARS scheme has the flexibility of choosing an ad hoc group of users, and signing on their behalf (like a ring signature). Furthermore, the signer can designate an opener who may later reveal his identity, if required (like a group signature). In 2015, Bootle et al. (ESORICS 2015) formalized the notion and gave an efficient construction for ARS with signature-size logarithmic in the size of the ring. Their scheme is proven to be secure in the random oracle model. Recently, Russell et al. (ESORICS 2016) gave a construction with constant signature-size that is secure in the standard model. Their scheme is based on q-type assumptions (q-SDH).In this paper, we give a new construction for ARS having the following properties: signature is constant-sized, secure in the standard model, and based on indistinguishability obfuscation (iO) and one-way functions. To the best of our knowledge, this is the first iO-based ARS scheme. Independent of this, our work can be viewed as a new application of puncturable programming and hidden sparse trigger techniques introduced by Sahai and Waters (STOC 2014) to design iO-based deniable encryption.
2017-11-03T00:00:00ZBosonic quantum Hall states in single layer 2D optical lattices
http://repository.iitgn.ac.in/handle/123456789/3532
Bosonic quantum Hall states in single layer 2D optical lattices
Bai, Rukmani; Bandyopadhyay, Soumik; Pal, Sukla; Suthar, K.; Angom, D.
Quantum Hall (QH) states of 2D single layer optical lattices are examined using Bose-Hubbard model (BHM) in presence of artificial gauge field. We study the QH states of both the homogeneous and inhomogeneous systems. For the homogeneous case we use cluster Gutzwiller mean field (CGMF) theory with cluster sizes ranging from�2�2�to�5�5. We, then, consider the inhomogeneous case, which is relevant to experimental realization. In this case, we use CGMF and exact diagonalization (ED). The ED studies are using lattice sizes ranging from�3�3�to�5�5. Our results show that the geometry of the QH states are sensitive to the magnetic flux�?�and cluster sizes. For homogeneous system, among various combinations of�1/5???1/2�and filling factor�?, only the QH state of�?=1/4�with�?=1/2,�1,�3/2�and�2�occur as ground states. For other combinations, the competing superfluid (SF) state is the ground state and QH state is metastable. For BHM with envelope potential all the QH states observed in homogeneous system exist for box potentials, but none for the harmonic potential. The QH states also persist for very shallow Gaussian envelope potential. As a possible experimental signature we study the two point correlations of the QH and SF states.
2018-02-01T00:00:00ZProbing parity violation in Neutron stars: I-Love-Q relations in dynamical Chern Simons Gravity
http://repository.iitgn.ac.in/handle/123456789/3529
Probing parity violation in Neutron stars: I-Love-Q relations in dynamical Chern Simons Gravity
Gupta, Toral; Majumder, Barun; Yagi, Kent; Yunes, Nicolas
2018-04-14T00:00:00ZBulk viscosity of a hot QCD/QGP medium in strong magnetic field within relaxation-time approximation
http://repository.iitgn.ac.in/handle/123456789/3533
Bulk viscosity of a hot QCD/QGP medium in strong magnetic field within relaxation-time approximation
Kurian, Manu; Chandra, Vinod
2018-02-01T00:00:00Z