Topic 1 : Will ‘colour molecules’ make quantum computers accessible?
Introduction
Many physical systems are suitable as qubits in a quantum computer, but most work only at a very low temperature. Researchers are working on alternative technologies to reduce costs, and thus also make quantum computers more commercially feasible.
Classical computer
- A classical computer is a collection of information storage units called bits.
- These physical devices have two states each, denoted 0 and 1.
- Any computation that a computer performs is essentially the result of the manipulation of the states of bits.
Qubit
- A qubit is a physical system with two quantum states, and it is the fundamental physical component of a quantum computer.
- A qubit can exist in one of the two states or — unlike classical computers — a superposed state with contributions from both states.
- Superposed states, also known as coherent superpositions, are important in quantum information-processing protocols.
- However, superpositions are fragile. The fragility arises out of the interaction between the qubit and other systems.
- The more the number of interaction channels, the faster the superposition “decoheres” and the qubit ends up in one of the two states.
Many qubits, one problem
- A collection of qubits is required to make a quantum device. For this, any group of qubits needs to satisfy a few basic requirements.
- One: the qubits should be identical. The qubits can’t be guaranteed to be identical since they need to be manufactured, and some ‘imperfections’ will creep in.
- Two: it should be relatively easy to integrate several qubits that can be operated controllably.
- Many different physical systems are suitable for realising qubits. Some well-studied and practical options include superconducting junctions, trapped ions, and quantum dots.
- In some cases, like superconducting junctions, a low temperature is in fact essential for them to work as qubits.
Commercial viability
- Quantum computers based on such technologies are expensive.
- Researchers are working on alternative, simpler technologies to reduce costs.
- Less expensive technologies will allow more participation in this research frontier.
- In a recent collaborative study reported in the journal Science Advances by a group of institutions in Japan, researchers realised qubits at room temperature in a metal-organic framework (MOF).
A MOF is a network of repeated molecular arrangements where the repeating structure has a metal atom or ion with organic molecules attached to it like tentacles. Each tentacle attaches to another metal atom, and the structure repeats itself to make up the MOF.
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The ‘colour molecules’
- In the system studied by the Japanese team, zirconium is the metal component and an organic molecule containing the chromophore pentacene bridges the metal atoms.
- A chromophore is an organic molecule or a part of a larger molecule that absorbs light of some specific colour.
- An object containing such molecules thus appears to have some dominant colour.
- Since the presence of chromophores is responsible for the colouration, they are also called “colour molecules”.
- When it absorbs light, the chromophore molecule jumps to a higher energy level (i.e. an excited state).
- In its lowest energy state, or ground state, a chromophore molecule has a pair of electrons in a special configuration called a singlet.
- Every electron possesses a property called spin that is inherent to it. The spin of an electron can point in two opposite directions, each corresponding to a distinct quantum state.
Role of singlet fission
- An excited molecular system has a small but non-zero chance of releasing its extra energy in a process called deexcitation.
- The higher energy singlet excited state can deexcite to a lower energy triplet excited state.
- The MOF networks are very porous, like sponges, allowing the chromophores to rotate by a small degree.
- The rotation leads to a change in the interaction strength between two adjacent chromophores.
Way forward
- It remains to be seen whether researchers can demonstrate how to achieve quantum gate operations on these qubits, assemble several qubits, and achieve controllability.
- Nevertheless, the availability of room-temperature qubits is a significant achievement that will invite many research groups to explore the system further.
Topic 2 : What is Bitcoin halving and what does it mean for the crypto community?
Introduction
Just as the sporting world eagerly awaits the Olympics every four years, those following cryptocurrency look forward to their own quadrennial event. As athletes train for the 2024 Games in Paris this summer, crypto traders and Bitcoin miners are preparing for what is known as the ‘Bitcoin halving’—predicted to happen in April.
Bitcoin halving refers to the 50% reduction in the reward paid to Bitcoin miners who successfully process other people’s cryptocurrency transactions so that they can be added to the public digital ledger known as the blockchain.
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‘Proof of work’
- In order to “grow” Bitcoin’s blockchain and keep the ecosystem running, Bitcoin miners rely on advanced computer equipment to solve a complex mathematical puzzle through a process known as ‘Proof of work.’
- This intense activity is the reason Bitcoin transactions result in huge carbon footprints and require vast amount of electricity. No real mining is carried out.
Impact on crypto investors
- Bitcoin mining increases the supply of BTC in circulation while Bitcoin halving reduces the rate at which these coins are released, making the asset more scarce.
- Scarcity is seen as pushing up prices, as is the case with gold.
- While there can only ever be 21 million BTC in the world, over 19 million have already been “mined” or released.
- This sounds like the end of the story, but Bitcoin halving means it will take far more time for the remaining coins to be mined.
- Both corporate and independent Bitcoin miners are spread across the world, trying to leverage cheap electricity prices in countries like Kazakhstan and Iran to mine as much Bitcoin as they can.
- China was originally home to many of the world’s crypto miners, but government crackdowns triggered an exodus to other countries.
Crypto market after Bitcoin halving
- Many Bitcoin investors and watchers also reference a recurring four-year cycle that hinges on the halvings, or even claim that prices spike after the halvings.
- But in reality, the coin’s journey has been far more unpredictable and difficult to map out.
- Every halving in Bitcoin’s history has been wildly different due to an eclectic mix of blockchain-related factors, increasing regulation by lawmakers worldwide, more awareness about cryptocurrency investments, greater adoption of Bitcoin, and diverse geopolitical events or economic shocks.
- Bitcoin is an asset whose price is largely steered by investors’ emotions, with there even being a ‘Fear and Greed’ indicator to help investors understand how prices could suddenly shift.
Conclusion
While the next Bitcoin halving will be a fascinating episode to witness, it is best for crypto watchers to rely on their own research and decide what the halving means to them personally.