A quantum computing in Indonesia with remarkable economic development. Bandung Institute of Technology has a long history of contributing to the development of science and technology, not only in Indonesia but also around the world. There is also active exchange with Japan, including RIKEN, JICA, and many universities.

*Q1. Since the middle of the 20th century, the university and Japan have been deepening their relationship. Please tell us about any memorable events during this period.*

A1: There have been extensive exchanges of experts, researchers, students, and professors between Indonesia and Japan since the 1950s. We have been sending students to Japanese universities since then; a crucial aspect in developing our human resources. I was one of those students. I did my PhD at the University of Tokyo under the Monbusho/Monbukagakusho Scholarship in 1999. I have learned a lot about academic and research cultures from the university.

*Q2. Student exchange is also very active. What is your impression of Japanese students?*

A2: We still run student exchange programs to this day. Having spent more time with Japanese students during my stay in Japan, I can say they are very kind and helpful to foreign students.

*Q3. What was the background to the establishment of the department on quantum technology?*

A3: We realize that quantum technology grows very fast and will have a huge impact on our lives. Since our School of Electrical Engineering and Informatics (STEI) of Institut Teknologi Bandung (ITB) is related directly to this field we have to anticipate the emergence of this new technology, and we have started by establishing a laboratory of quantum technology (QLAB-STEI). I’ve been fortunate to have educational backgrounds in both Physics and Electrical Engineering. When I started my PhD back then, I really wanted to study quantum information but very few professors offered such a research topic at that time. I was happy when I got a topic on complex-valued signal processing and neural networks. I considered it close enough to quantum computing, at least they both use complex numbers.

Recently, the field of quantum technology has grown very fast; we have got a timely momentum. Some quantum information devices are already available, we can obtain them as photonics or electronics components, and some quantum computers are accessible by public users. I think now is the right time to start quantum technology activities in our school.

*Q4. What kind of research is being conducted in the Quantum Laboratory now? How many people are involved?*

A4: The QLAB-STEI was established just recently in 2021. Our main activities include research, development, and education related to quantum technology. However, we are now at a very early stage in preparing our lab; I mean that the equipment and the number of researchers are very limited at this time. At present, we have less than 10 members, a few students, and some experts from various institutions; including those from foreign research centres, start-ups, and companies. Some of the young STEI faculty members are still taking graduate degrees in the field of quantum technology.

*Q5. What kind of research is being done in the laboratory? Can you give us some concrete examples?*

A5: We start by developing quantum algorithms. This is a natural choice because we can easily access quantum computer hardware in the cloud. So, for the research, we can do both the simulation and running on a real quantum processor. We have a student who works on quantum machine learning and another one on traffic optimization. I have been working on finding Hadamard matrices. I chose this topic because it is an interesting hard problem with various kinds of scientific and engineering applications. The interesting part of solving this problem is that at first, it looks so easy but really it is not. In this problem, you have a square matrix with binary elements, -1 and 1, and you have to arrange them such that each pair of columns or rows is orthogonal. It is very easy to verify whether your answer is correct or not, which can be done in polynomial time by multiplying the matrix by its transpose. But arranging the -1 and 1 elements to get an orthogonal matrix is extremely hard. We have employed various kinds of algorithms; initially with the Simulated Annealing (SA), then Simulated Quantum Annealing (SQA), and later when we had access to the quantum processor DWAVE, we developed a Quantum Annealing (QA) algorithm. An MxM size, or M-order matrix, should have needed an O(M2) qubits but implementation on quantum annealer needs O(M3) qubits due to the limitation of the present days QA processor to implement only up to 2-body interaction (Ising Hamiltonian) so that we need additional ancillary qubits for higher-order interactions.

In our 2019 published paper [1], we successfully find 2 and 4 order Hadamard matrices by using the D-Wave machine. Later, by “quantizing” some of the classical methods, we can reduce the required number of qubits into just O(M2) if it is implemented on a quantum annealer. Early this year, we published the results of finding the Hadamard matrix order of 108; and as a bonus, one of the methods discovered the Hadamard matrix of order 92; which was a long-sought matrix that was finally discovered by JPL researchers in the 1960s [2]. We expect to further increase qubit efficiency into O(M) by employing a universal gate quantum processor. The ultimate goal will be discovering unknown Hadamard matrices, such as the Hadamard matrices of order 668, 716, 892, … etc. Those matrices cannot be discovered by classical computers implementing known algorithms so discovering them by using a quantum computer will be something like a demonstration of practical quantum supremacy, which is the following stage after Google’s quantum supremacy achievement in 2019. We think that it will be one of the “creative” algorithms referred to in the 2019 Google paper.

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NB: links to our papers in Scientific Reports, in case they are needed

- https://www.nature.com/articles/s41598-019-50473-w
- https://www.nature.com/articles/s41598-021-03586-0

*Q6. In Indonesia, which is developing rapidly, how do you see the government and industry approaching quantum technology?*

A6: At present, quantum technology is still progressing in academic and research institutions. We haven’t yet seen any nationwide initiative on quantum technology. But I suppose things will change in the near future. The Indonesian government is rather open to the emergence of new technologies with a direct impact on societies. Our national research agency is undergoing a reorganization, and I believe quantum technology should be considered seriously as one of its main agendas. Not to mention some companies from the private sector will be interested in this technology as well. At the moment our industry is observing the development of this technology. They will move in this direction at the right time.

*Q7. What expectations do you have for the industry regarding quantum technology?*

A7: The innovations in quantum technologies are fast-growing; I hope that a few of them will soon be mature enough and ready for production. For Indonesia, I hope that we can anticipate such rapid development by starting to think seriously and take initiative in quantum technology at the national level.

*Q8. What are your expectations for the future of quantum technology in the world?*

A8: I think this field grows very fast. The number of quantum annealing qubits doubles every two years, the universal gate is expected to reach one thousand qubits in the next couple of years, and is predicted to achieve 1 million qubits by 2030. The quality of the qubits, such as the coherence time or the error rate, is significantly enhanced by the development of new methods. Silicon-based quantum processors increased their fidelity. Some quantum-based and post-quantum cryptography (QKD: Quantum Key Distribution) are steadily enhanced and will soon be widely used as the field of quantum computing advances, due to the fear that conventional encryption will soon collapse. The application of quantum computing in finding new materials, drug discovery, and hard optimization will also be intensely investigated.

*Q9. What are your hopes for quantum technology in the world?*

A9: We know that quantum technology, the so-called second quantum revolution, will transform our lives in unprecedented manners. I hope it will open the windows of new possibilities unimaginable by us today and improve the quality of our lives.