Uploaded October 2020 | Updated September 2026, 2 hours ago
A new technology for building computers is on the rise. Derived from quantum mechanics, today we will be discussing the properties of quantum computers and what makes them so special when compared to classical computers. We will also be looking at why we should care about this new technology when we already have very powerful supercomputers.
A classical computer contains microchips that contain transistors that allow the flow of information in the form of bits. A bit is a binary digit and is the smallest increment of data on a computer. It can hold only one of two values: 0 or 1, corresponding to the electrical values of off or on in a transistor respectively. Combinations of many bits representing a 0 or a 1 are used to store more complex information and compute more complex problems. Since each bit can only be a 0 or a 1 at any given instance, solving problems such as optimal routes from point A to Point B can consume vast amounts of time on a classical computer.
A quantum computer, on the other hand, does not use transistors or classical bits. It uses quantum bits or q-bits that can represent a 0 or a 1 or both of these states at the same time, based on the principle of superposition. It is this property that gives quantum computers the potential to be millions of times faster than even the classical super-computers.
Suppose we have 2 bits on a classical computer, this means there are a total of 2^2 possible configurations out of which we can choose only one. However, 2 q-bits in a state of superposition in a quantum computer can be in all 2^2 configurations at once making calculations on a quantum computer exponentially faster. As long as the q-bit is unobserved, it will be in all possible states only collapsing to a definite value of 0 or 1 when it is observed making it a regular classical computer.
To counter this problem of observation, scientists make use of another property of quantum mechanics, known as entanglement, to make measurements indirectly and preserve the system's integrity. So, in principle, if an external force is applied to two q-bits, they can become entangled. Once this happens, measuring the state of one q-bit will be enough to deduce the state of the second q-bit without having to directly observe it.
Combining these two principles, q-bits can become an extremely advanced version of switches solving problems that would be impossible to do using a classical super-computer. In general, given n bits and n q-bits, a classical computer can perform 2^n operations one by one, whereas a quantum computer can simultaneously perform all 2^n operations at once. This means that having only a few 100 q-bits will already be faster at problem-solving than some of our computers with billions and billions of bits today. So, what kind of problems will a quantum computer solve for us?
Quantum computers can be used to solve many unsolved problems. For example, they can be used to accurately model molecular interactions leading to breakthroughs in medicine as well as solving optimization problems such as finding the best possible route between two cities cutting the cost down tremendously. Accurate weather forecasting and climate change models will also become readily available. Moreover, quantum computers will be able to break very large numbers into their prime factorization revolutionizing cryptography. In general, quantum computers will be able to solve problems with small inputs and very large outputs due to their special quantum properties. They can even advance our understanding of physics and mathematics by helping to model complex particles and solving very difficult mathematical problems, which would be impossible to solve on a classical computer.
A new technology for building computers is on the rise. Derived from quantum mechanics, today we will be discussing the properties of quantum computers and what makes them so special when compared to classical computers. We will also be looking at why we should care about this new technology when we already have very powerful supercomputers.
A classical computer contains microchips that contain transistors that allow the flow of information in the form of bits. A bit is a binary digit and is the smallest increment of data on a computer. It can hold only one of two values: 0 or 1, corresponding to the electrical values of off or on in a transistor respectively. Combinations of many bits representing a 0 or a 1 are used to store more complex information and compute more complex problems. Since each bit can only be a 0 or a 1 at any given instance, solving problems such as optimal routes from point A to Point B can consume vast amounts of time on a classical computer.
A quantum computer, on the other hand, does not use transistors or classical bits. It uses quantum bits or q-bits that can represent a 0 or a 1 or both of these states at the same time, based on the principle of superposition. It is this property that gives quantum computers the potential to be millions of times faster than even the classical super-computers.
Suppose we have 2 bits on a classical computer, this means there are a total of 2^2 possible configurations out of which we can choose only one. However, 2 q-bits in a state of superposition in a quantum computer can be in all 2^2 configurations at once making calculations on a quantum computer exponentially faster. As long as the q-bit is unobserved, it will be in all possible states only collapsing to a definite value of 0 or 1 when it is observed making it a regular classical computer.
To counter this problem of observation, scientists make use of another property of quantum mechanics, known as entanglement, to make measurements indirectly and preserve the system's integrity. So, in principle, if an external force is applied to two q-bits, they can become entangled. Once this happens, measuring the state of one q-bit will be enough to deduce the state of the second q-bit without having to directly observe it.
Combining these two principles, q-bits can become an extremely advanced version of switches solving problems that would be impossible to do using a classical super-computer. In general, given n bits and n q-bits, a classical computer can perform 2^n operations one by one, whereas a quantum computer can simultaneously perform all 2^n operations at once. This means that having only a few 100 q-bits will already be faster at problem-solving than some of our computers with billions and billions of bits today. So, what kind of problems will a quantum computer solve for us?
Quantum computers can be used to solve many unsolved problems. For example, they can be used to accurately model molecular interactions leading to breakthroughs in medicine as well as solving optimization problems such as finding the best possible route between two cities cutting the cost down tremendously. Accurate weather forecasting and climate change models will also become readily available. Moreover, quantum computers will be able to break very large numbers into their prime factorization revolutionizing cryptography. In general, quantum computers will be able to solve problems with small inputs and very large outputs due to their special quantum properties. They can even advance our understanding of physics and mathematics by helping to model complex particles and solving very difficult mathematical problems, which would be impossible to solve on a classical computer.
