Qubits

Extracted Attributes

• Field

  Quantum Computing, Quantum Information Science

• States

  Can exist in a superposition of 0 and 1 simultaneously

• Function

  Enables quantum computation intractable for classical computers

• Analogue to

  Classical binary bit

• Concept Type

  Fundamental unit of quantum information

• Core Principle

  Interference

• Physical Realizations

  Spin of an electron, Polarization of a photon, Trapped ions, Artificial atoms, Superconducting circuits

Qubit

In quantum computing, a qubit () or quantum bit is a basic unit of quantum information—the quantum version of the classic binary bit physically realized with a two-state device. A qubit is a two-state (or two-level) quantum-mechanical system, one of the simplest quantum systems displaying the peculiarity of quantum mechanics. Examples include the spin of the electron in which the two levels can be taken as spin up and spin down; or the polarization of a single photon in which the two spin states (left-handed and the right-handed circular polarization) can also be measured as horizontal and vertical linear polarization. In a classical system, a bit would have to be in one state or the other. However, quantum mechanics allows the qubit to be in a coherent superposition of multiple states simultaneously, a property that is fundamental to quantum mechanics and quantum computing.

Web Search Results

• What is a qubit? - Quantum Inspire

  A qubit (or quantum bit) is the quantum mechanical analogue of a classical bit. In classical computing the information is encoded in bits, where each bit can have the value zero or one. In quantum computing the information is encoded in qubits. A qubit is a two-level quantum system where the two basis qubit states are usually written as ∣0⟩ and ∣1⟩. A qubit can be in state ∣0⟩, ∣1⟩ or (unlike a classical bit) in a linear combination of both states. The name of this phenomenon is superposition.

• How do qubits allow for quantum computation, and what are they?

  Qubit stands for Quantum Binary Digit. Qubit is the elementary unit of quantum information, just like a bit is the elementary unit of classical information. In fact, you may consider qubit to be a unit vector in a two-dimensional Linear Vector Space. For example, state of an electron in an atom with just energy levels, state of polarization of a photon, state of spin of an electron, etc. [...] Qubit stands for Quantum Binary Digit. Qubit is the elementary unit of quantum information, just like a bit is the elementary unit of classical information. In fact, you may consider qubit to be a unit vector in a two-dimensional Linear Vector Space. For example, state of an electron in an atom with just energy levels, state of polarization of a photon, state of spin of an electron, etc. [...] A qubit is the quantum equivalent of a bit. Because it’s the quantum version, it’s not limited to a state of 0 or 1; you can rotate it through a quantum gate to get 0.5 or 0.31512893472 or any other state between 0 and 1. The state can then be collapsed by measurement to a classical 0 or 1 state. This allows a lot more flexibility than is possible with a bit, showing one advantage of quantum computing.

• What is a Qubit? | Microsoft Azure

  A qubit uses the quantum mechanical phenomena of superposition to achieve a linear combination of two states. A classical binary bit can only represent a single binary value, such as 0 or 1, meaning that it can only be in one of two possible states. A qubit, however, can represent a 0, a 1, or any proportion of 0 and 1 in superposition of both states, with a certain probability of being a 0 and a certain probability of being a 1. [...] Where classical computers use familiar silicon-based chips, qubits (sometimes called "quantum computer qubits") can be made from trapped ions, photons, artificial or real atoms, or quasiparticles. Depending on the architecture and qubit systems, some implementations need their qubits to be kept at temperatures close to absolute zero. Image 2: Qubit vs bit representation Superposition, interference, and entanglement --------------------------------------------- [...] More The future of qubits Resources Free account Qubit explained --------------- Just like a binary bit is the basic unit of information in classical (or traditional) computing, a qubit (or quantum bit) is the basic unit of information in quantum computing. Quantum computing is driving new discoveries in healthcare, energy, environmental systems, smart materials, and beyond. Qubit vs bit ------------ ### Qubits are represented by a superposition of multiple possible states

• Qubits | Institute for Quantum Computing - University of Waterloo

  A quantum bitis any bit made out of a quantum system, like an electron or photon. Just like classical bits, a quantum bit must have two distinct states: one representing “0” and one representing “1”. Unlike a classical bit, a quantum bit can also exist in superposition states, be subjected to incompatible measurements, and even be entangled with other quantum bits. Having the ability to harness the powers of superposition, interference and entanglement makes qubits fundamentally different and

• What's a Qubit? 3 Ways Scientists Build Quantum Computers

  Today’s smartphones, laptops and supercomputers contain billions of tiny electronic processing elements called transistors that are switched either on or off, signifying a 1 or a 0 in the binary language computers use to express and calculate all information. Qubits are essentially quantum transistors. They can exist in two well-defined states—say, up and down—which represent 1 and 0. But they can also occupy both those states at the same time, which adds to their computing prowess. And two—or [...] A superconducting qubit is typically a tiny loop or line of metal that behaves like an atom—an inherently quantum object. The two states of the qubit correspond to two energy states of this artificial atom: its lowest energy state, which is known as the ground state, and the next one up. The states are initiated and controlled using microwave pulses. [...] more—qubits can be entangled, a strange quantum phenomenon in which particles’ states correlate even if the particles lie across the universe from each other. This ability completely changes how computations can be carried out, and it is part of what makes quantum computers so powerful, says Nathalie de Leon, a quantum physicist at Princeton University. Furthermore, simply observing a qubit can change its behavior, a feature that de Leon says might create even more of a quantum benefit. “Qubits