Nonvolatile and Cryogenic-compatible Quantum Memory Devices (QuMEM)
Osama M. Nayfeh, Kenneth S. Simonsen, Dave Rees, Naderi, Shahrokh, Anna Leese de Escobar, Dinh, Son, Escobar, Fernando, B. J. Taylor, Marcio de Andrade, Susan A. E. Berggren, Swanson, Paul, Bruce W. Offord
Abstract : This technical report presents the progress of the Space and Naval Warfare Systems Center Pacific (SSC Pacific) Nonvolatile and Cryogenic-Compatible Quantum Memory Devices (QuMEM) research project supported by the Navys Science and Technology (S and T) In-house Laboratory Independent for Research (ILIR) Program. This report provides background information, motivation, technical progress, and technology transition efforts conducted throughout Fiscal Year (FY) 2014.The primary objective of the QuMEM project is to design and implement novel concepts, designs for solid-state, cryogenic compatible quantum memory device chips where writing, reading, and erasing operations perform using fast (psec), low-voltage (mV) electrical pulses generated by on-chip computational devices. Here, quantum states are generated, tuned, and stored for computation. We increase the understanding of the memory storage process by characterizing the charging/discharging process, retention time, and endurance and how it correlates with design-driven theoretical calculations.
Abstract : This technical report presents the progress of the Space and Naval Warfare Systems Center Pacific (SSC Pacific) Nonvolatile and Cryogenic-Compatible Quantum Memory Devices (QuMEM) research project supported by the Navys Science and Technology (S and T) In-house Laboratory Independent for Research (ILIR) Program. This report provides background information, motivation, technical progress, and technology transition efforts conducted throughout Fiscal Year (FY) 2014.The primary objective of the QuMEM project is to design and implement novel concepts, designs for solid-state, cryogenic compatible quantum memory device chips where writing, reading, and erasing operations perform using fast (psec), low-voltage (mV) electrical pulses generated by on-chip computational devices. Here, quantum states are generated, tuned, and stored for computation. We increase the understanding of the memory storage process by characterizing the charging/discharging process, retention time, and endurance and how it correlates with design-driven theoretical calculations.
Over the past decade, quantum computers have emerged as a promising technology to enable transformational advances in information processing and communication and solve problems that are intractable to classical computers. While there is great promise in linking quantum computers together over long distances via quantum channels, these technologies are still under development. Solid-state emitters with coherent spin-photon interfaces, long spin lifetimes, and narrow optical transitions are a leading platform for use as quantum memories in networked quantum repeaters. However, while such emitters have already enabled advanced quantum networking demonstrations in laboratory settings, applying these devices as useful memory devices at scale is a key outstanding challenge. In this thesis, we experimentally investigate solid-state quantum memories for quantum information applications. First, we develop experimental techniques to characterize solid-state emitters with high throughput, enabling both better understanding of the distribution of emitter properties and improved feedback on material preparation and device fabrication. Next, we implement quantum frequency conversion to create a coherent spin-photon interface between silicon-vacancy centers in diamond and optical photons in the low-loss telecom band. Finally, we investigate color centers in other engineering materials, including silicon and silicon carbide, to better understand the fundamental trade space of requirements for solid-state hosts. Together, these efforts represent a significant advance in creating, controlling, and deploying telecom-compatible spin interfaces, paving the way for memory-enabled quantum repeaters.
A quantum computer can solve fundamentally difficult problems by utilizing properties of quantum bits (qubits). It consists of a quantum substrate, connected to a conventional computer, termed as control processor. A control processor can manipulate and measure the state of the qubits and act as an interface between qubits and the programmer. Unfortunately, qubits are extremely noise-sensitive, and to minimize the noise; qubits are operated at cryogenic temperatures. To build a scalable quantum computer, a control processor which can work at cryogenic temperatures is essential [3, 14]. In this paper, we focus on the challenges of building a memory system for a cryogenic control processor. A scalable quantum computer will require large memory capacity for storing the program and the data generated by the quantum error correction. To this end, we evaluate the feasibility of cryogenic DRAM-based memory system by characterizing commercial DRAM modules at cryogenic temperatures. In this paper, we report the minimum operational temperature for 55 DIMMs (consisting of a total of 750 DRAM chips) and analyze the error patterns in commodity DRAM devices operated at cryogenic temperatures. Our study shows that a significant fraction of DRAM chips continue to work at temperatures as low as 80K. This study is an initial step towards evaluating the effectiveness of cryogenic DRAM as a main memory for quantum computers.
This work provides a novel concept for a voltage-programmable quantum memory with capability to tune superconducting qubits. Electric field-induced ion transport in Superconductor-Ionic hetero-structures programs the tunneling current and Hamiltonian [1]. This work develops a model of the field-effect in the superconducting state at resonance. We use the model to simulate designs of memory devices programmable with sub-50 milli-Volt and sub-nanosecond pulses while maintaining 1-10 year storage time [2]. Quantum Master Equation (QME) simulations [3] support tuning of the time dependent quantum coherence properties in these devices with a programmed Hamiltonian determined by unique ion energy levels. To obtain further insights, we construct Niobium/AlOx/Ionic-HfOx/AlOx/Niobium devices and characterize the effects of key experimental parameters. The work provides device technology advances applicable to cryogenic computing and quantum information [4-6].
Cryogenic (cryo) memory devices, designed to operate at/below 4 Kelvin (K) temperature, is a prime enabler of practical quantum computing systems, and superconducting (SC) electronic platforms (Figs. 1(a), (b)) [1]. The state-of-the-art quantum algorithms require many arbitrary rotations which demand a large memory to store program instructions [2]. SC qubits (used in most of the existing quantum computing systems) are highly sensitive to noise and hence, to protect the qubit states from thermal disturbances, they are placed at a few milli-Kelvin (mK) temperature. Furthermore, to preserve the integrity of the quantum states, the SC qubits undergo continuous error correction schemes, requiring extensive memory and bandwidth [2]. Superconducting electronics (SCE) (targeted towards space applications, and high-performance computing) outperforms the conventional CMOS counterparts in terms of speed and energy-efficiency (Fig. 1(c)) [3]. Decades of research efforts have given rise to three major categories (and several sub-variants) of cryo-memories based on SC, non-SC, and hybrid technologies (Fig. 2) [2], [4]–[6]. However, the existing variants suffer from one or more of the following challenges - (i) limited scalability, (ii) process complexity, (iii) bulky peripherals, (iv) array-level interference, (v) volatility, and (vi) speed incompatibility. Therefore, a scalable cryo-memory system remains elusive. To address these existing issues, here, we present a novel cryo-memory system utilizing -(i) the polarization-induced Cooper-pair [7] modulation in a ferroelectric(FE)superconducting quantum interference device (SQUID) (Fig. 3(a)) [8], and (ii) current controlledSC↔non−SCswitching in a heater cryotron(hTron)(Fig. 4) [4]. Discrete prototypes of these devices have been demonstrated recently, but their coupled interactions (which we harness in our work) were never explored before.
Compared to traditional multivalued computing systems, multivalued quantum computing offers more processing power and uniqueness thanks to its combination of theoretical computer science and quantum physics.It uses quantum mechanics and the collective features of quantum states, such as superposition with entanglement, and interference, to accomplish some calculations with unprecedented computational speed.When dealing with these intricate issues, quantum algorithms adopt a novel strategy: they generate multidimensional spaces from which the patterns connecting distinct data points arise.These algorithms could effectively address complex mathematical problems, generate secure codes that are difficult to crack, and predict interactions among multiple particles in chemical reactions.They also refer to memory devices, a general term for integrated circuits that can be programmed in a lab to carry out intricate functions.Quantum computers outperform traditional Turing machines by coherent superposition of states.Large photonic quantum processing systems would be possible with the help of quantum memories since they would be capable of effectively modifying, buffering, and adjusting the timing of photonic signals.While qubits can only be used as input states in certain types of computers, quantum computing allows for the development of new computer types that have higher storage capacities despite the slower performance of regular programmable read-only memory (PROM).The design of multivalued quantum-based PROM is a key concern in order to produce affordable, durable, high-capacity, reliable, and energy-efficient memory systems.This study presents the construction of a multivalued PROM architecture based on quantum mechanics, utilizing algorithms for multiple valued quantum ternary operations.
Abstract Quantum memory devices are essential components of integrated quantum-photonic circuits with applications in quantum computing and quantum information processing. The comprehension and quantification of critical properties such as fidelity, coherence time, storage time, and efficiency of quantum memory are insufficient in the extant literature. In this review, we examine the development and characteristics of various types of quantum memories. Although diverse approaches to storing quantum information are described in detail, we emphasize solid-state quantum memory. Furthermore, we discuss the fabrication and characterization of defects of quantum materials, including two-dimensional materials, for quantum memory applications. We survey theoretical tools such as density functional theory for studying defects to evaluate quantum properties.