Gil Kalai (born 1955) is an Israeli mathematician and computer scientist. He is the Henry and Manya Noskwith Professor Emeritus of Mathematics at the Hebrew University of Jerusalem, Israel, Professor of Computer Science at the Interdisciplinary Center, Herzliya, and adjunct Professor of mathematics and of computer science at Yale University, United States.[1]
Kalai is a quantum computing skeptic who argues that true (classically unattainable) quantum computing will not be achieved because the necessary quality of quantum error correction cannot be reached.
Conjecture 1 (No quantum error correction). The process for creating a quantum error-correcting code will necessarily lead to a mixture of the desired codewords with undesired codewords. The probability of the undesired codewords is uniformly bounded away from zero. (In every implementation of quantum error-correcting codes with one encoded qubit, the probability of not getting the intended qubit is at least some δ > 0, independently of the number of qubits used for encoding.)
Conjecture 2. A noisy quantum computer is subject to noise in which information leaks for two substantially entangled qubits have a substantial positive correlation.
Conjecture 3. In any quantum computer at a highly entangled state there will be a strong effect of error-synchronization.
Conjecture 4. Noisy quantum processes are subject to detrimental noise.[9]
Recognition
Kalai was the winner of the 2012 Rothschild Prize in mathematics.[10] He was named to the 2023 class of Fellows of the American Mathematical Society, "for contributions to combinatorics, convexity, and their applications, as well as to the exposition and communication of mathematics".[11]