The Quantum Dictionary

Quantum technology is one of the fastest-growing fields in the world – and it comes with a vocabulary all its own. We’ve put together this dictionary so that anyone exploring the IQMP’s website, our partners or Illinois’ broader innovation ecosystem can quickly get up to speed on the key terms and concepts that come up most often in the quantum space.

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“Classical” or Conventional Computing 

• The traditional way computers process information, using electrical signals represented as 0s and 1s to carry out tasks step by step. It’s the foundation of the technology we rely on everyday, like laptops and smartphones, and the baseline against which quantum computing’s capabilities are measured. 

 

Cryotechnology 

• The study and application of extremely low temperatures, close to what scientists call “absolute zero.” Quantum computers typically require ultra-cold conditions to operate, because even the slightest amount of heat can introduce errors into a quantum system. 

 

Cryoplant 

• An industrial facility that cools gases such as helium to extremely low temperatures, and that may convert the gas into liquid for storage and transport. Cryoplants serve a wide range of industries – including energy, manufacturing and healthcare – and will be a critical part of the infrastructure that supports large-scale quantum computing. 

 

End users

• The individuals or organizations that ultimately use a product or technology in real-world situations – essentially, the customers. In the quantum space, end users will apply quantum technology to solve complex problems, improve operations or drive advances in their industries. 

 

Electron Spins in Silicon

• Refers to a property of electrons – their intrinsic “spin,” or magnetism – that can be used as a qubit. Using silicon leverages the industrial scale processes used to fabricate the chips in conventional computing, making this a promising approach to building reliable quantum computers. 

 

Entanglement (“Quantum Entanglement”) 

• A phenomenon where two quantum particles become linked such that a change to one automatically affects the other, no matter how far apart they are. It’s one of the most distinctive and powerful features of quantum physics, and a key driver of why quantum computing is so promising. 

 

Fault Tolerance

• Referring to a computer system’s ability to detect and respond to failures in its hardware or software. A fault-tolerant quantum computer is designed so that errors on qubits can be detected and corrected in real time, which is critical as quantum technology moves toward real-world deployment. 

 

Quantum Algorithm

• A set of instructions that tells a quantum computer how to approach a problem and arrive at a solution. Algorithms are the software side of quantum computing and essential for translating the raw power of quantum hardware into practical applications across industries. 

 

Quantum Computing

• Uses the principles of quantum mechanics to solve certain complex problems faster than traditional computers. Instead of the electrical 0s and 1s used in classical computing, quantum computers use quantum bits (qubits) made from systems obeying the laws of quantum mechanics, giving them the potential to tackle challenges in fields ranging from medicine to materials science to national security.

 

Quantum Mechanics 

• The branch of physics that studies the smallest building blocks of the universe – matter, energy and light – and how they interact. It describes a world where particles can behave like both particles and waves at the same time. This is the underlying science behind technologies we already use, like lasers and transistors and medical imaging. 

 

Qubit (a.k.a. quantum bit)

• The basic unit of information used in quantum computing, equivalent to the “bit” in classical computing. While a classical bit can only be a 0 or 1, a qubit can exist in a combination of both states at once (superposition), which lets quantum computers process many possibilities at the same time. 

 

Microelectronics 

• The field focused on the study, manufacture and use of very small electronic components – most notably microchips, which are tiny but extremely complex machines central to modern technology. In the quantum space, microelectronics serves as an enabling technology, helping to build and advance the hardware that quantum computers depend on. 

 

Neutral Atoms 

• Atoms that carry no electric charge, occurring when the number of protons and electrons in an atom are equal. Because of their stable, controllable and reproducible properties, neutral atoms can be used as qubits, making them one of several promising building blocks for quantum computers. 

 

Noise

• Referring to the unwanted disturbances that interfere with quantum systems and introduce errors into computations. It’s one of the most significant engineering challenges in the field, because even minor disruptions can cause qubits to lose their stability. This makes the pursuit of reliable, large-scale quantum computers an ongoing area of intensive research.

 

Photons 

• The smallest possible units of light. Photons carry energy across the entire spectrum of electromagnetic radiation, from radio waves to visible light to gamma rays, and are being explored as a potential basis for certain types of quantum computing. 

 

Scale-up 

• The process of increasing the size, capacity or output of a system that works in a controlled setting, and expanding it into a full-scale, real-world operation. In quantum computing, scaling up is one of the industry’s defining challenges: moving from small prototypes to systems powerful and stable enough for commercial use. 

 

Silicon Transistors 

• Semiconductor devices made from silicon that control or amplify electrical currents, serving as the most fundamental building block of modern electronic circuits. The most common type is metal oxide semiconductor field effect transistors (MOSFETs) – a component so foundational that it underpins nearly all of today’s digital technology. 

 

Superconducting Circuits

• Electrical circuits made from metals that, when cooled to near absolute zero, lose all electrical resistance – meaning energy flows through them without any loss. In quantum computing, these circuits are engineered to behave like artificial atoms, with energy levels that can be controlled and measured to function as qubits.   

 

Superposition 

• The quantum principle that says a particle can exist in multiple states at the same time. This property allows quantum computers to process a vast number of possibilities simultaneously, which is part of why they have the potential to outperform classical computers on certain types of problems. 

 

Trapped Ions

• Atoms that carry an electric charge and are held in place in a vacuum using electric fields and controlled with precisely tuned laser beams. Because the ions are identical and naturally stable, trapped ion technologies are a promising way to build quantum computers.