Probabilistic Bits - p-bits


Bridging the gap between classical bits and quantum bits

Classical computing is based on a bit, a device that can be either a ‘0’ or a ‘1’, but not both at the same time, which switches only when an operation occurs. In contrast, quantum computing is based on a quantum bit (q-bit or qubit), a device that is represented as a quantum superposition of ‘0’ and ‘1’ at the same time. A third type of device, distinct from the other two, is a classical probabilistic bit or p-bit, which naturally fluctuates between ‘0’ and ‘1’. A research group at Purdue University, under the direction of Prof. Supriyo Datta, has shown how these types of p-bits can provide the basis for a type of probabilistic computing.

The authors suggest that these devices can be implemented using low-barrier magnetic memory cells similar to those in conventional memory technologies. They further indicate that the p-bit may represent a “poor-man’s qubit”, and that systems of p-bits can be used to address some problems that might otherwise seem to require quantum computing, such as quantum annealing. Furthermore, they can also be used as binary stochastic neurons for stochastic machine learning.

The paper, “P-Bits for Probabilistic Spin Logic”, by Kerem Cansari, Brian Sutton, and Supriyo Datta, is available here.

A brief overview of this work is available here.