IBM has made a major breakthrough in quantum computing by linking two cryogenic modules capable of reaching temperatures about 180 times colder than deep space, or just 0.015 kelvin—barely 15 thousandths of a degree above absolute zero. This is an essential step toward creating quantum computers with hundreds of qubits and fault-tolerant capabilities. For context, the cosmic microwave background radiation, a remnant of the Big Bang, has a temperature of about 2.7 kelvin, making the temperatures IBM has achieved extremely cold by comparison. Such extreme cold is necessary because superconducting qubits, the building blocks of many quantum computers, are highly sensitive to their environment. Heat can create thermal noise that disrupts their quantum state, leading to errors in calculations. To protect them, quantum processors are placed in dilution refrigerators that use a mix of helium-3 and helium-4 to cool them to just a few thousandths of a kelvin. Until now, quantum communication systems that required repeaters relied on classical models, which posed a security risk. However, a recent breakthrough has provided a solution for quantum repeaters, which are essential for long-distance quantum communication. Scaling up the number of qubits has presented a major challenge in terms of cooling and system design. Each qubit needs to be controlled, read, and connected to the rest of the system, which requires more cables and interconnections that can introduce heat and noise. IBM has addressed this by moving away from a single, large cryostat to a modular approach using rectangular cryogenic cells that can be connected side by side. Each cell has its own vacuum chamber, cooling system, and thermal shields. When two cells are combined, their protections create a continuous cryogenic tunnel through which the connections between processors can pass. The first two connected modules are over 2.4 meters tall and wide. They were cooled to 4 kelvin in less than five days before reaching less than 15 millikelvin. Each module offers up to twelve times more space for wiring than IBM’s typical systems, and their box-like shape allows the processors to be placed closer together, reducing the length of connections between them. Scientists from MIT have shown that some classical physics concepts can describe the peculiar behaviors observed at the quantum level, aiding in the development of more reliable systems. IBM is working on deploying "L-couplers," interconnections designed to transfer quantum information between different chips, enabling multiple processors to function as parts of a single quantum machine. IBM plans to test this new architecture by installing Nighthawk processors in the modules as early as 2027. The goal is to connect several processors to create a system with at least 1,000 programmable qubits. In the long term, each cryogenic cell could host thousands of qubits. This progress is expected to lead to Starling, IBM’s planned quantum computer for 2029, which will feature 200 error-corrected logical qubits capable of performing up to 100 million quantum operations. This represents a significant leap toward practical, large-scale quantum computing.