# K. Rajibul Islam

## Biography

Dr. Rajibul Islam's research interests are in quantum information processing, in particular quantum simulation and computation. His research team is building a quantum simulator with laser-cooled trapped ions to simulate models of interacting quantum many-particle systems. Dr. Islam is also involved in building 'QuantumIon', a multi-user, open-access trapped-ion quantum computer at Waterloo.

## Research Interests

- Experimental quantum many-body physics with ultra-cold atomic ions
- Quantum Computing
- Entanglement in strongly correlated matter, experimental schemes to measure entanglement
- Frustrated spin systems, and their experimental realization with synthetic cold matter
- Fully connected spin networks using trapped ions
- Quantum Materials
- Quantum Science
- Photonics
- Quantum Information Processing
- Quantum Simulation

## Scholarly Research

Many outstanding problems of modern physics involve understanding the origin and properties of strongly interacting quantum systems. Such correlated quantum systems – such as the high-Tc superconductors and quark-gluon plasma in a particle collider – are present in various energy scales. In an interacting quantum system, entanglement or non-classical correlations between parts often makes theoretical or numerical analysis intractable. An experimental way to solve this problem is to simulate quantum models using well-controlled quantum systems in the laboratory. In these experimental ‘quantum simulators’, it is possible to add complexities and increase the system size in a controlled way. The long quantum coherence in these systems allow their temporal evolution following the quantum laws of nature. The task of the experimentalist is then to initialize the system in a known state, engineer the desired quantum Hamiltonian, let the system evolve in isolation from its environment, and finally measure the outcome. The knowledge gained from studying non-trivial quantum models can potentially lead to the understanding of exotic quantum phases of matter, and give fundamental insights towards realizing quantum computers.
The main research focus of the QITI laboratory is to use laser-cooled trapped ions to simulate non-trivial quantum Hamiltonians. The long range Coulomb interaction between the ions would be exploited to engineer versatile spin Hamiltonians. The spin interactions can be tuned, in principle arbitrarily, and the individual spins can be detected with near perfection. Multi-spin interactions can be created, allowing us to study interacting (spinless) Fermions. Further, the phonons associated with the collective vibrational modes enable us to study interacting bosonic Hamiltonians, such as the Bose-Hubbard model. While trapped ions normally have long quantum coherence, one can introduce dissipation in a controlled way for studying open quantum systems. Interacting Hamiltonians and open quantum systems are often hard to simulate on classical computers, and may become intractable beyond 30-40 spins. The QITI laboratory aims to work in the regime where classical computation is difficult or intractable.

## Education

- 2012 Ph.D. in Physics, University of Maryland, College Park
- 2007 M.Sc. in Physics, Tata Institute of Fundamental Research, Mumbai
- 2005 B.Sc. in Physics, Jadavpur University, Kolkata

## Awards

- Early Researcher Award, Ontario Government (2019)
- Distinguished PhD Dissertation Award, University of Maryland (2012-13)

## Affiliations and Volunteer Work

- Faculty, Institute for Quantum Computing

## Teaching*

- PHYS 234 - Quantum Physics 1
- Taught in 2019, 2020, 2021, 2022

- PHYS 256 - Geometrical and Physical Optics
- Taught in 2018, 2022

- PHYS 393 - Physical Optics
- Taught in 2020, 2022

- PHYS 701 - Quantum Mechanics 1
- Taught in 2022

* Only courses taught in the past 5 years are displayed.

## Selected/Recent Publications

- Machine learning design of a trapped-ion quantum spin simulator Y. H. Teoh, M. Drygala, R. G. Melko, and R. Islam. Quantum Sci. Technol. 5, 024001, (2020); arXiv:1910.02496
- Dynamical Hamiltonian engineering of 2D rectangular lattices in a one-dimensional ion chain F. Rajabi, S. Motlakunta, C. Shih, N. Kotibhaskar, Q. Quraishi, A. Ajoy, and R. Islam. npj Quantum Inf 5, 32, (2019); arXiv:1808.06124
- Measuring entanglement entropy in a quantum many-body system Rajibul Islam, Ruichao Ma, Philipp M. Preiss, M. Eric Tai, Alexander Lukin, Matthew Rispoli, and Markus Greiner. Nature 528, 77 (2015), Nature News and Views
- Strongly Correlated Quantum Walks in Optical Lattices Philipp M. Preiss, Ruichao Ma, M. Eric Tai, Alexander Lukin, Matthew Rispoli, Philip Zupancic, Yoav Lahini, Rajibul Islam, and Markus Greiner Science 347, 6225 (2015), Science Perspective, arXiv:1409.3100
- Emergence and Frustration of Magnetic Order with Variable-Range Interactions in a Trapped Ion Quantum Simulator R. Islam, C. Senko, W. C. Campbell, S. Korenblit, J. Smith, A. Lee, E. E. Edwards, C.-C. J. Wang, J. K. Freericks, and C. Monroe, Science 340, 583 (2013), arXiv1210.0142
- Onset of a Quantum Phase Transition with a Trapped Ion Quantum Simulator R. Islam, E. E. Edwards, K. Kim, S. Korenblit, C. Noh, H. Carmichael, G.-D.Lin, L.-M. Duan, C.-C. Wang, J. K. Freericks and C. Monroe Nature Communications 2:377 (2011) arXiv:1103.2400, JQI press release
- Reprogrammable and high-precision holographic optical addressing of trapped ions for scalable quantum control - npj Quantum Information
- Programmable quantum simulations of spin systems with trapped ions