Why Do Quantum Computers Need to Be Cold? Explained [2025]

 

Why do quantum computers need to be cold? The answer lies in the delicate nature of quantum states and the impact of temperature on their stability. In this article, we will explore the reasons behind the need for cooling, the science of quantum coherence, and how temperature affects the performance of quantum systems.

 

 

Why Quantum Computers Need to Be Cold

Quantum computers need to be cold primarily due to the nature of quantum mechanics and the delicate quantum states that they rely on to perform computations. Here's why:

 

Quantum Superposition and Coherence

Quantum computers leverage quantum bits (qubits), which can exist in multiple states simultaneously—a phenomenon known as superposition.

These quantum states are highly sensitive to their environment. Any interaction with the outside world, like thermal vibrations or electromagnetic interference, can cause quantum states to collapse prematurely. This disruption is called "decoherence."

Cooling the quantum system minimizes these thermal interactions, allowing the qubits to maintain their delicate superpositions longer.

 

Minimizing Thermal Energy

At higher temperatures, atoms and particles are more active due to thermal energy, which leads to increased vibrations and noise.

These vibrations can interfere with the quantum states, causing errors in computations. By cooling the system to near absolute zero (often using dilution refrigerators), thermal energy is reduced, minimizing these disruptions and allowing the qubits to perform their tasks more accurately.

 

Superconductivity in Some Quantum Systems

Many quantum computers, especially those based on superconducting qubits (like those developed by companies like SpinQ and Google), rely on superconductivity—a phenomenon where certain materials can conduct electricity without resistance when cooled to very low temperatures.

Superconductivity is critical for the operation of these qubits, as it allows them to maintain quantum states without energy loss.

 

Reducing Background Radiation and Noise

At higher temperatures, the system is more likely to interact with the surrounding electromagnetic radiation, which can introduce noise into the quantum system. Cooling helps reduce the effect of this background radiation, ensuring that quantum operations are more stable.

 

 

How Cold is Cold Enough for Quantum Computers?

The temperature required for quantum computing varies depending on the technology used to create the qubits. However, most quantum computers operate at temperatures between 10 millikelvins (-273.14°C) and 100 millikelvins (-273.15°C). To put this in perspective, these temperatures are colder than deep space!

In some quantum computing systems, like those based on superconducting qubits, the qubits must be cooled using dilution refrigerators, which can reach these ultra-cold temperatures. These specialized refrigerators use a mixture of helium-3 and helium-4 to achieve temperatures close to absolute zero.

In other quantum systems, such as those using trapped ions or topological qubits, the cooling requirements may differ, but low temperatures are still essential for maintaining the quantum states of the qubits.

 

 

Challenges in Maintaining Cold Temperatures for Quantum Computers

While cooling is necessary for quantum computers to function properly, it also presents several challenges.

The complexity of maintaining such low temperatures requires specialized equipment, such as dilution refrigerators, which are both technically demanding and expensive.

Additionally, quantum systems are highly sensitive to external factors, meaning even slight fluctuations in temperature, magnetic fields, or electromagnetic radiation can negatively impact their performance.

Furthermore, as quantum computers scale up, maintaining the ultra-cold conditions for a larger number of qubits becomes increasingly difficult. Researchers are working on developing new cooling methods and improving the stability of quantum systems to handle larger quantum processors in the future.

 

SpinQ offers comprehensive cryogenic environment deployment services to ensure that quantum computers operate in stable and high-performance experimental settings. These services include:

Dilution Refrigerators

Cryogenic Components and Devices:

Superconducting Quantum Computing Lab Assessment / Cryogenic Device Installation:

Supporting Equipment for Cryogenic System

 

By leveraging SpinQ's expertise and services, organizations can effectively navigate the complexities of maintaining the ultra-cold environments necessary for optimal quantum computer performance.