Techniques for quantum memory addressing and related systems and methods
Inventors
Hann, Connor • Zou, Changling • Chu, Yiwen • Zhang, Yaxing • Schoelkopf, III, Robert J. • Girvin, Steven M. • Jiang, Liang
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-12450001-B2
Publication Date
2025-10-21
Expiration Date
Abstract
Techniques for implementing a QRAM by routing quantum information through multiple modes of a bosonic system are described. According to some aspects, a single bosonic system may be configured to maintain quantum information in a large number of independent modes at the same time. Suitable operations upon these modes may allow a quantum address value to be routed to modes associated with respective bits such that the only modes altered by the operations are those associated with the addresses being accessed. These modes may be operated upon based on the stored values then extracted to obtain the desired correlated superposition of the stored bit values in the addresses. The bits stored at the address locations may be classical bits, or may be qubits.
Core Innovation
The invention relates to quantum random access memory (QRAM) implemented using a quantum router that operates a superconducting circuit coupled to a bosonic system. The bosonic system exhibits non-uniformity in a frequency spacing of at least some modes, so that address routing is performed through those non-uniformly spaced modes.
A plurality of address qubits is initialized with values based on the quantum address, where each address qubit is represented by a respective mode of the bosonic system. A plurality of register qubits is also initialized, where each register qubit is represented by a respective mode of the bosonic system. Quantum gates are then performed by providing energy to the superconducting circuit, changing a state of at least one register qubit based at least in part on a state of one address qubit.
The invention further includes performing, by providing energy to the superconducting circuit, a phase shift of one or more of the plurality of register qubits according to values stored in the memory. This enables extraction of correlated, superposed data corresponding to addressed memory locations, and enables selective coupling via engineered non-uniform frequency spacing and compact routing that scales with order log2(N), including parallelizable downstream/upstream routing.
Claims Coverage
The partial content includes two independent claims. Across these independent claims, there are three main inventive feature themes: a quantum-router based method for accessing memory using a quantum address conditioned on address-qubit states; non-uniform frequency spacing in the bosonic system; and QRAM system-level control that applies energy to a superconducting circuit using a quantum address representing superposed address locations.
Quantum router with superconducting circuit coupled to a non-uniform bosonic system
Operating a quantum router that comprises a superconducting circuit coupled to a bosonic system, where the bosonic system exhibits non-uniformity in a frequency spacing of at least some modes.
Initialize bosonic modes as address qubits and register qubits for quantum-addressed access
Initializing a plurality of address qubits with values based on the quantum address, wherein each address qubit is represented by a respective mode of the bosonic system, and initializing a plurality of register qubits, wherein each register qubit is represented by a respective mode of the bosonic system.
Address-conditioned gates and memory-value phase shifts via the superconducting circuit
Performing a plurality of quantum gates by providing energy to the superconducting circuit, each quantum gate changing a state of at least one register qubit based at least in part on a state of one address qubit, and performing a phase shift of one or more register qubits according to values stored in the memory by providing energy to the superconducting circuit.
QRAM system controller manipulating bosonic-mode states using a quantum address superposition
A QRAM system comprising a memory, a quantum router with a superconducting circuit comprising at least one non-linear element and a bosonic system coupled to the superconducting circuit that exhibits non-uniformity in a frequency spacing of at least some modes, and at least one controller configured to manipulate states of modes of the bosonic system by applying energy to the superconducting circuit based on a quantum address representing a superposition of address locations within the memory.
The independent claim set covers a QRAM access mechanism that uses a superconducting-circuit quantum router coupled to a bosonic system with non-uniform mode frequency spacing. Address and register qubits are represented by bosonic modes, quantum gates are applied by energy to the superconducting circuit conditioned on address-qubit states, and register qubits receive phase shifts according to values stored in memory.
Stated Advantages
Selective coupling enabled by engineered non-uniform frequency spacing.
Compact routing scaling in order log2(N), with parallelizable downstream/upstream routing.
Documented Applications
Quantum random access memory (QRAM) for accessing memory using a quantum address representing superposed address locations, including extracting correlated data corresponding to addressed memory locations.
Interested in licensing this patent?