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QTran Lab – Pushing the Boundaries of Quantum Device Technology

India is making significant strides in developing its quantum capabilities, with the National Quantum Mission (NQM) serving as a key driver of this advancement. Contributing to this mission, Quantum Transport Lab at IISER Thiruvananthapuram researches quantum transport phenomena, focusing on device design, fabrication, and low-temperature measurements to enhance quantum properties, discover new phenomena, and explore potential technological applications. QTran Lab was the first research group in India to get a Bluefors system, in 2017.

Exploring the Potential of Quantum Transport

Quantum transport research is at the forefront of understanding the behavior of particles and information at the quantum level. This field investigates how electrons and other quantum particles move, interact, and transmit information in nanoscale systems. Through researching the fundamental principles of quantum transport, insights can be gained into the behavior of matter at its smallest scales.

Dr. Madhu Thalakulam, an Associate Professor at the School of Physics in the Indian Institute of Science Education & Research (IISER) Thiruvananthapuram, leads the QTran Lab. “The outlook of our lab is to study, tailor, and utilize various quantum transport phenomena for improving our understanding of fundamental problems, pushing the limits, and revolutionizing device technology,” Madhu explains.

QTran Lab focuses on three primary research areas.

  1. Quantum Dot Spin Qubits on Silicon Platforms: QTran Lab develops quantum dots that serve as qubits, the essential building blocks of quantum computers, by leveraging silicon’s compatibility with current semiconductor technology.
  2. Quantum Electrical Amplifiers: QTran Lab works on achieving quantum-limited electrical amplification , enabling ultra-sensitive detectors for a wide range of applications.
  3. Two-Dimensional Superconductivity and Van der Waals Superconducting Circuits: QTran Lab explores new superconducting states and circuits that could lead to the development of next-generation quantum devices.

One important figure of merit for any scientific phenomenon is its applicability and potential uses in device technology . QTran Lab investigates the potential applications of quantum transport phenomena. Madhu summarizes the work of his team: “We focus on device design, fabrication, and low-temperature measurements to enhance the quantum mechanical properties in transport, uncover new quantum phenomena, and explore device or technological applications. This involves extensive nano-scale device fabrication and low-noise electrical measurements.”

Birds-eye view of the activities in QTran Lab; Quantum electrical amplifiers, multiqubit processor based on quantum dot spin qubit on Silicon platform, and two-dimensional superconducting systems (left to right). Photo: Madhu Thalakulam / QTran Lab

India’s Quantum Mission

Madhu highlights the role of India’s National Quantum Mission (NQM), initiated by the Prime Minister’s Science, Technology and Innovation Advisory Council (PM-STIAC), as a major step in advancing the country’s quantum research capabilities. “The NQM aims to foster, develop, and scale up scientific and industrial R&D in the quantum field, helping India bridge the gap with more technologically advanced nations . The mission is expected to drive the development of cutting-edge technologies across several areas,” Madhu says.

The key focus areas of the NQM include quantum computing, quantum communication, quantum sensing and metrology, and quantum materials and devices. The mission’s ambitious goals target milestones such as intermediate-scale quantum computers with 50-1000 physical qubits, secure satellite-based quantum communications, inter-city quantum key distribution over 2000 km, and multi-node quantum networks with quantum memories.

QTran Lab is a proud contributor to this mission. “In India, solid-state qubit research has a very small footprint. We are one of only a few experimental research groups in the country involved in solid-state quantum processor development and the only group working on quantum electrical amplifiers,” Madhu says.

“Besides developing quantum processors based on spin-qubits, we also aim to achieve the quantum limit in electrical amplification; we’ve already demonstrated shot-noise-limited, ultra-fast electrical amplifiers.”

In addition, QTran Lab excels in two-dimensional superconductivity and superconducting circuits. “In the 2021 quantum materials roadmap published by the Institute of Physics, our work on 2D superconductivity and Bose metal states on 1T-MoS2 was the only one featured from India. I’m glad to mention that this experiment was carried out on a Bluefors LD250 system.”

LD System as the Backbone of QTRAN Lab

QTran Lab acquired its first LD 250 cryogenic measurement system in 2017, making it the first Bluefors system in India. Madhu notes: “It has been performing without any blemish for the last 7-8 years. The LD250 fridge is the backbone of our measurements: it has been used for research on quantum electrical amplifiers and investigations into two-dimensional superconductivity. The LD system is also the main attraction for any lab visitors.”

The QTran Lab team customized the system to fit their specific research needs. “We have re-wired the entire system. All cryogenic microwave filters and low pass RC and LC filters are designed and fabricated in-house and the installations are done by our own highly skilled graduate students. After all the modifications, the system still maintains a base temperature of 10 mK, thanks to its robust and modular design,” Madhu explains.

In early 2024, a new LD250 system was installed at QTran Lab, with wiring specifically reworked for spin-qubit research. The original system was also relocated. Madhu says, “It was as smooth and pleasant as a breeze. Both the Bluefors and the VT Vacuum engineers were incredibly helpful, making the process a valuable learning experience for our newer students who weren’t involved in the initial installation.”

Relocated LD system and the new LD system at QTran Lab. Photo: Madhu Thalakulam / QTran Lab

Shaping Tomorrow’s Technologies

The scientific advances achieved through harnessing quantum phenomena hold the potential to revolutionize communications, medicine, navigation, and our understanding of the universe. “Quantum technology is set to influence all branches of science and aspects of everyday life. There are many day-to-day technologies in many fields that rely already, or will rely, on quantum-enabled technologies. For example banking, education and the health sector, as well as national security,” Madhu explains.

“While quantum computing and qubit research are at the forefront of the field, quantum sensing, and metrology are also rapidly advancing. In this context, electrical amplifiers, like voltage and charge amplifiers, are especially important because they can easily connect charge or voltage to other factors such as capacitance, strain, and displacement. This capability allows for quantum-limited detection of various parameters. For example, it could enable an all-electrical way to sense phenomena like gravitational waves. Devices such as Josephson parametric amplifiers and quantum point contact charge amplifiers show great promise in this area.”

Madhu also notes the transformative potential of van der Waals materials – a class of layered materials held together by weak van der Waals forces, allowing them to be easily thinned down to a few atomic layers. These materials have unique electronic and optical properties, and Madhu believes this makes the van der Waals material platform poised to revolutionize existing quantum technology.

Pushing Boundaries with Bluefors

Bluefors helps scientists push the boundaries of current knowledge, not only by providing reliable cooling systems, but also supporting those systems throughout their lifetimes – allowing researchers to focus on achieving milestone research long into the future. “Regarding technical support, I have no other words to say other than excellent. The Bluefors technical team was always available, and the instructions were very educative for us to take care of any similar problems in the future,” Madhu says.

Reflecting on his decision to purchase the Bluefors system, Madhu shares: “I received positive feedback from colleagues in the USA and UK, which encouraged me to buy the Bluefors system. Since the beginning, our interaction with Bluefors has been very smooth. We never felt that we were interacting with a company, rather an academic partner.”

At Bluefors, we work closely with our customers to find the best solutions tailored to their specific needs. Find out more about Bluefors LD systems and discover the wide range of applications where Bluefors technology is utilized.