Prof. Arindam Ghosh of IISc builds light detectors from atom-thin materials. He would happily see RSA encryption broken if it meant a working quantum computer, and he hopes quantum sensors will one day put brain imaging in a helmet.
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Quantum technology is engineering on physics nobody fully understands, Ghosh says, and that is no obstacle. He maps it as three verticals — computing, sensing and communication — on a horizontal of materials and devices. A useful quantum computer was once thought to need a billion qubits; by his count it is now about 10,000. What remains is engineering, but engineering that still needs basic research. Sensing gets less attention, though almost anything measured today could be measured more finely with a quantum sensor, he says. His advice to founders: pick the use case first, then learn only the quantum it needs.
Disclosure: Prof. Ghosh is a co-founder of Quan2D Technologies, an IISc-incubated startup working on 2D materials and quantum-sensing devices. He does not mention it on air, though he discusses quantum sensing and quantum startups at length.
Figures are as said on air; field strengths and milestone years are typical published values. Sources: National Quantum Mission (PIB), post-quantum standards (NIST), prize citation (Infosys Science Foundation). Click ▶ to hear it.
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Checked against the record: the award is the Infosys Prize 2020 in Physical Sciences; the introduction calls it the “Infosys Laureate Prize”. MRI does not measure the brain’s own magnetic field; it reads radio signals from hydrogen nuclei inside a strong magnet. The brain’s field, about 100 fT, is measured by magnetoencephalography (MEG), and the wearable helmets now in trials are MEG scanners built on optically pumped magnetometers, a quantum sensor (said: “the MRI machines measure magnetic field of the brain”, “a handheld MRI”). In quantum key distribution the photons set up the shared secret; the two sides use an ordinary authenticated channel only to compare settings, so no public key is exchanged (said: “a public key that is exchanged”). Real QKD systems have been attacked through hardware flaws. NIST asks organizations to move to post-quantum standards as soon as possible, because data encrypted today can be stored now and decrypted later; its draft transition plan deprecates RSA after 2030 and disallows it after 2035. The first transistor (germanium, Bell Labs) dates from 1947 and the first microprocessor, Intel’s 4004, from 1971, 24 years later; personal computers spread in the 1980s (said: “40 years from 1950s”).