JPH11102584A - Improved logic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved logic apparatus utilizing a spin system as a logic device/memory unit. SOLUTION: A continuous waveform RF (resonant radio frequency) output from a resonant radio frequency source 21 is supplied to a modifier/driver 22 connected to a pulser 29 generating d.c. gating pulses. A resulting RF pulse is connected to a power amplifier 23, and an output part of the power amplifier is connected to a probe head 27 accommodating a spin system at the center of a magnetic field 26. An output part of the probe head 27 is connected to a preamplifier/receiver obtaining a reference input from an RF source and an output part of the preamplifier/receiver 24 is connected to a computer apparatus 30 through an analog-digital converter 25. The other input part of the probe 27 is connected to a gradient control unit 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to an improved logic device. The improved logic device of the present invention provides an interactive or non-interactive spin-1
/ 2 sets of magnetic resonance based fast logic implementations. Such high-speed logic devices form a key feature of new or hybrid spin computers.

[0002]

BACKGROUND OF THE INVENTION At a basic level, a logical system is:
It is substantially based on an array of bi-state switches. Conventional logic devices are based on silicon semiconductor technology. The two states of the system are referred to as a "high" state and a "low" state, which typically correspond to voltages of 5V and 0V, respectively.

[0003] The computer is based on the logical system shown in FIG. 1 and includes an arithmetic logic unit 1, a central processing unit 2 and a memory 3. When operating on the arithmetic logic unit 1, the memory 3 acts to “store” information that can be quickly accessed by the central processing unit 2. Modern computer memories are typically "volatile" dynamic random access memories (DRA).
M), where the memory cells are refreshed periodically. A typical computer is a device in which data is processed "in series.""Parallel" architectures are also of great interest, resulting in significantly faster operating speeds. Parallel architectures are currently implemented based on arrays of semiconductor-computer based nodes.

[0004] Apart from multiple developments in semiconductor-based logic and computer systems, "molecular computers" based primarily on molecular switches have recently been developed as alternatives to possible specific applications. In particular, "computers for proteins" and "computers for DNA"
However, there has been particular interest in a number of recent studies. It can be mentioned here that the development of other architectures such as these may lead to even applications that cannot be considered at present.

[0005] LMAdleman (Science 266, 1021, 1994)
, RJ Lipton (Science, 268, 542, 1995) and RRBirg
e (Scientific American, 272, 66, 1995), the current tremendous effort in the development of bimolecular computers has been specifically directed to protein computers using bacteriorhodopsin, and more recently Rather, it is directed to DNA computers.

In a molecular computer, information is stored during molecular switching, which means forming, breaking or reorienting molecular bonds that require a measure of the amount of molecular binding and interaction energy. . The reusability of a logic device is significantly shorter than that of a normal silicon device.

[0007]

Five years after the discovery of each spin echo, Proctor et al. (Journal of Applied Physics,
26, 170, 1955) and Hahn et al. (Journal of Applied Physi
cs, 26, 1324 1955: Scientific American, 251, 42,19
84) presented possible uses for each spin system as a storage device. This is called “registration” during linear response management of the spin system.
It employs an echo phenomenon in which a sequence of events is called in a reverse order by spin echo or in a normal order by stimulated echo. No other developments on this have been reported so far, presumably because this is a relatively slow device. A block diagram of such a storage device using each spin system is shown in FIG. In FIG. 2, reference numeral 4 denotes an RF (resonance frequency) source, and reference numeral 5 denotes a modulator /
Reference numeral 6 denotes a driver, 6 denotes a pulser, 7 denotes a power amplifier, 8 denotes a preamplifier / receiver, 9 denotes an oscilloscope, 10 denotes a pole of a magnet, and 11 denotes a probe.

It is an object of the present invention to provide an improved logic device utilizing a spin system as a logic device / storage unit.

Another object of the present invention is to reduce the energy of storing and reading information as compared to a molecular computer.

Still another object of the present invention is to increase reusability (lifetime) as compared with a general molecular computer.

It is yet another object of the present invention to integrate information storage and processing into a single device so that it can act as a key feature in the development of a hybrid semiconductor and spin computer.

[0012]

SUMMARY OF THE INVENTION An improved logic device according to the present invention comprises a resonant radio frequency (RF) source having a continuous waveform (CW) RF output that generates a DC gating pulse. A modulator / driver connected to the pulser is supplied, the resulting RF pulse is connected to a power amplifier, and the output of the power amplifier is connected to a probe head containing a spin system at the center of the magnetic field. A conventional computer device that can connect the output of the probe head to a preamplifier / receiver that obtains a reference input from the RF source, and control the timing and performance of the output of the preamplifier / receiver through an analog-to-digital converter. To connect the other input of the probe to the spin-based storage element It is characterized by being connected to a gradient control unit capable of generating orthogonal gradient pulses.

[0013]

FIG. 3 shows an RF source 12, which may be a common fixed or variable frequency oscillator or synthesizer. This produces a continuous waveform (CW) RF output at a predetermined frequency.

Numeral 13 denotes a modulator / driver, which generates the required RF pulses by modulating the CW RF input from 12 with the DC gating pulses from 19 and converts it to power amplification. Buffer.

Reference numeral 14 denotes a power amplifier, which is a power amplifier.
Has a variable computer controlled attenuator at its output.

Reference numeral 15 denotes a preamplifier / receiver, which receives, amplifies, and detects the phase of the analog signal from 18 with reference to the reference signal from 12.

16 is an analog-digital converter (A
DC), which is a high speed and high resolution unit that converts 15 analog outputs to digital data.

Reference numeral 17 indicates the poles of the magnet, which sets up the bistable state of the spin system.

Reference numeral 18 denotes a probe head which accommodates the spin system in the center of a magnetic field surrounding the spin system by one or more radio frequency (RF) coils tuned to one or more resonance frequencies. , 14 and route the signal to 15.

Reference numeral 19 denotes a pulser, which generates the required DC gating pulse pattern either directly by hardware or under software control.

Reference numeral 20 denotes a standard computer device.
This controls the timing and performance of the rest of the hardware.

In FIG. 4, reference numeral 21 denotes an RF source, which can be a general fixed frequency or variable frequency oscillator or synthesizer. This produces a continuous waveform (CW) RF output at a predetermined frequency.

Numeral 22 indicates a modulator / driver which generates the required RF pulse by modulating the CW RF input from 29 with the DC gating pulse from 21 and converts it to power amplification. Buffer.

Reference numeral 23 denotes a power amplifier, which is a power amplifier.
Has a variable computer controlled attenuator at its output.

Reference numeral 24 denotes a preamplifier / receiver, which receives, amplifies and detects the phase of the analog signal from 21 with reference to the reference signal from 27.

Reference numeral 25 denotes an analog-to-digital converter (A
DC), which is a high speed and high resolution unit that converts 24 analog outputs to digital data.

26 indicates the poles of the magnet, which sets up the bistable state of the spin system.

Reference numeral 27 denotes a probe head, which accommodates the spin system in the center of a magnetic field surrounding the spin system by one or more radio frequency coils tuned to one or more resonance frequencies, and an RF power from 23. And 2
4 and generate a magnetic field gradient under the control of 28 in cooperation with the gradient coil.

Reference numeral 28 denotes a gradient control unit by which any combination of three orthogonal gradient patterns can be set up and released in addressing the "storage element" of the spin system.

Numeral 29 denotes a pulser, which generates the required DC gating pulse pattern either directly by hardware or under software control.

30 indicates a standard computer device,
This controls the timing and performance of the rest of the hardware.

The present invention provides: a) a spin system having a sufficiently long relaxation time in a magnetic field to provide a bistable state; and b) a system using magnetic resonance excitation and detection to access the bistable state. C) providing an improved logic device comprising a magnetic field gradient that allows "addressing" of individual memory "cells" of the spin system.

Therefore, the present invention provides a continuous wave (CW)
A modulator / driver (2) comprising a resonant radio frequency (RF) source having an RF output, the CW RF output being connected to a pulser (29) for generating a DC gating pulse.
2) and the resulting RF pulse is connected to a power amplifier (23) and the output of said power amplifier is
A probe head (27) for accommodating a spin system at the center of the magnetic field (26), and an output of the probe head (27) connected to a preamplifier / receiver for obtaining a reference input from the RF source (12); A conventional computer device (30) capable of controlling the timing and performance of the output of the preamplifier / receiver (24) through an analog-to-digital converter (ADC)
And the other input of the probe (27) is connected to a gradient control unit (28) capable of generating a quadrature gradient pulse for addressing the spin-based storage element. Logical device provided.

In an embodiment of the present invention, the spin system used in the present invention has an ESR (electron spin resonance) line width of up to 1 MHz and / or an ENDOR (electron nuclear double resonance) line width of up to 1 MHz. It can have an NMR line width of up to 1 MHz.

In another embodiment of the present invention, the external magnetic field is generated by a permanent magnet, an electromagnet, a superconducting electromagnet, or a fringe magnetic field of a superconducting electromagnet. The spin system is taken from a probe, also known as a probe head, tuned to one or more resonance frequencies and placed in an external magnetic field. Under this circumstance, the system behaves as a bistable state system, with each spin having two possible spin orientations-upward and downward half. The “up” spin state is referred to as a logic level “high”, while the other, ie, “down” spin state, is referred to as a logic level “low”.

Data is "written" by controlling the orientation of the spins, which consists of magnetic field pulses, resonant RF
It is controlled using a suitable system console by suitable means such as the application of a pulse or microwave pulse or the passage of a non-uniform magnetic field. The data, ie the spin orientation, is read again by applying any of the previous methods or by a superconducting quantum interferometer (SQUID). The time scale required to write or read the electron spin orientation by using a resonance pulse is a measure of 1 to 10 ns.

The resonance RF pulse with, it is possible to change the spin orientation when "resonance" frequency v ₀ burst appropriate radiation. This resonance frequency is given in terms of the strength of the applied magnetic field B ₀ by the following equation: 2v ₀ = νB ₀ . Here, ν is the gyromagnetic ratio, which is constant for a particular spin system.

The system console illustrated in FIGS. 3 and 4 comprises a stable fixed frequency RF source, the output of which is fed to the modulator gated by the pulsed DC pulse output. The frequency of operation of the RF source is determined by the strength of the magnetic field in which the probe is located and the identity of the spin system used in the logic device. The strength of the magnetic field is shown in FIGS.
Indicated by the poles. The output of the modulator / driver is provided to a power amplifier having a variable computer controlled attenuator at its output. The pulser may be a simple standard wired device, or a complex computer-excited standard device that allows for the automated execution of complex excitation / detection pulses as described in logical form below. The RF pulse output from this amplifier is supplied to a single coil or cross coil excitation / detection probe head, which houses the spin system and is placed in a magnetic field. The signal output from the probe head is provided to a phase sensitive broadband receiver, the demodulated output of which is a high speed (about 10 MHz) digitizer or 300 MHZ.
sampled by a signal sampler having a sampling frequency in the range of z to 2 GHz and finally a computer /
Stored in the peripheral device.

The following basic form of pulse rotation is used during data "writing" starting with a spin system during thermal equilibrium. The spin system rotates the spin of the longitudinal axis by a predetermined angle parallel or anti-parallel to the magnetic field, corresponding to the establishment of a particular logic state of the bistable system.

Another 180 ° rotation corresponds to a rotation of another logic state. This is achieved by the resonance means already described.

On the other hand, in order to “read” data, it is necessary to use the following pulse rotation mode.

The spins are “tilted” to the intersection plane and the “start” point of free induction decay (FID) is between 1 ns and 100 ms.
And re-oriented to the original state by reversing the pulse rotation.

The "polarity" of the "starting point" of the resulting FID has relevant information.

The "read" procedure as described above ends with the recovery of the initial spin state corresponding to the "read" operation without changing the logic state of the system.

The signal from the probe head is detected and demodulated by a pulse detection receiver and a high speed signal sampler. This is a method of reading “data”. The probe head is placed in a magnetic field that applies the desired pulse / constant magnetic field gradient to the sample in any combination of three mutually orthogonal directions, referred to as the x, y and z directions, so that the memory Addressing becomes possible. An RF power amplifier having a pulse forming function is optionally used for addressing. The realization of the logical form is achieved by means of suitable modulation of the resonant RF using a pulser and a modulator to generate the desired pattern of spin pulse rotation.

The following examples are given by the present invention, but they do not limit the scope of the invention.

Example 1 As a conductive polymer, a crystal of fluoranthene hexafluorophosphate is selected as a spin system. This polymer is
A durable paramagnetic type with a narrow (20 KHz) ESR line width. It is a long electron spin “relaxation time”. The polymer sample is taken out to a probe head and placed in a magnetic field of a variable magnetic field electromagnet to set up an electron spin resonance state. The magnet is 0.010
Operating at a nominal magnetic field strength of 7T, which corresponds to an electron spin resonance frequency of 300 MHz. The current stability of the power supply of the electromagnet is about 1 ppm, while the uniformity of the magnetic field over 1 cm ² is about 10-20 ppm. Bruker MSL30 using low power excitation by the low power output channel of the system decoupler for resonant excitation of the spin system
Performed by a 0 P FT NMR spectrometer, using assembler level programming to generate the smallest possible pulse duration (about 400-500 ns). The pulse amplitude is varied at this constant pulse duration to achieve various desired tilt ("flip") angles. Spin resonance is captured using a 10 MHz digitizer. The following basic pulse rotation format is used during data "writing" and starts with a spin system during thermal equilibrium. 360 ° pulse rotation corresponding to logic state “0” 180 ° pulse rotation corresponding to logic state “1” In contrast, to read data, the following pulse rotation format is used. 90 °° pulse rotation—sample “start” point of FID during time of 8 μs 90 180 ° -8 μs-90 ° pulse rotation. 0 270 The “polarity” of the “starting point” of the resulting FID is relevant information, eg, '+ ve' polarity corresponding to logic state “0” '−ve' polarity corresponding to logic state “1”

By using the above-described device, one-bit information can be stored and then read.

EXAMPLE 2 Water, ie narrow (3 Hz) NMR (nuclear magnetic resonance)
A diamagnetic type having a line width of is selected as a spin system. It also retains the property of a long nuclear spin "relaxation time". This sample was taken out to the probe head and
A 300 MHz nuclear magnetic resonance is set up by placing in the magnetic field of a superconducting electromagnet of a fixed magnetic field of T strength. The uniformity of the magnetic field of 1 cm ³ is about 0.01 ppm. Bruka MS using resonant excitation of spin system with low power excitation by low power output channel of system decoupler
Performed by L 300 P FT NMR spectrometer,
Use assembler level programming to generate the smallest possible pulse duration (about 128 μs). The pulse amplitude is varied at this constant pulse duration to achieve various desired tilt ("flip") angles. Spin resonance is captured using a 125 KHz digitizer. The following basic pulse rotation format is used during data "writing" and starts with a spin system during thermal equilibrium. 360 ° pulse rotation corresponding to logic state “0” 180 ° pulse rotation corresponding to logic state “1” In contrast, to read data, the following pulse rotation format is used. 90 °° pulse rotation—sample “start” point of FID during 20 μs time 90 180 ° -20 ° -90 ° pulse rotation. 0 270 The “polarity” of the “start point” of the resulting FID is relevant information, eg, '+ ve' polarity corresponding to logic state “0” '−ve' polarity corresponding to logic state “1”

By using the above device, one-bit information can be stored and then read.

Addressing is performed using a pulsed magnetic field gradient generated by a probe head using a gradient amplification system with an amplitude gradient of 0.0007 Tcm ^-1 .

EXAMPLE 3 Solid polymethyl methacrylate protons (PMMA) are selected as the spin system. The PMMA is removed to the probe head and placed on the fringe of the magnetic field of a fixed field superconducting electromagnet with a fringe field strength of about 2.75T, 118
Set up for nuclear magnetic spin resonance at MHz. The uniformity of the magnetic field corresponds to about 30 Tm ^-1 .

Resonant excitation of the system is performed on a Bruker MSL 300 P FT NMR spectrometer console using high power excitation by the system's high power transmission unit and using assembly level programming for about 400-500 ns. Generate the smallest possible pulse duration. The pulse amplitude is varied at this constant pulse duration to achieve various desired tilt ("flip") angles. Spin resonance is captured by a 125 KHz / 10 MHz digitizer.

The following basic pulse rotation format is used during data "writing" and starts with a spin system during thermal equilibrium. 360 ° pulse rotation corresponding to logic state “0” 180 ° pulse rotation corresponding to logic state “1” In contrast, to read data, the following pulse rotation format is used. 90 °° pulse rotation—sample “start” point of FID during 20 μs time 90 180 ° -20 ° -90 ° pulse rotation. 0 270 The “polarity” of the “start point” of the resulting FID is relevant information, eg, '+ ve' polarity corresponding to logic state “0” '−ve' polarity corresponding to logic state “1”

By using the above device, one-bit information can be stored and then read.

The main advantages of the improved logic device of the present invention are as follows. 1. The device can "write" or "store" and "read" data defined by the pulse rotation of the spin system. 2. Unlike sequential storage in spin storage, memory access is possible in arbitrary and / or parallel modes. 3. Higher reusability compared to standard molecular systems. 4. Information storage and processing can be integrated. 5. Unique parallel processing becomes possible. 6. Unlike molecular computers, half-spin systems are completely bistable systems.

[Brief description of the drawings]

FIG. 1 is a block diagram of a standard semiconductor-based computer.

FIG. 2 shows a standard magnetic resonance apparatus for generating spin echoes and stimulated echoes.

FIG. 3 is a block diagram of an embodiment of the device of the present invention without an addressing function.

FIG. 4 is a block diagram of another embodiment of the improved logic device of the present invention having a memory addressing function.

[Explanation of symbols]

 Reference Signs List 1 arithmetic logic unit 2 central processing unit 3 memory 4, 12, 21 RF source 5, 13, 22 modulator / driver 6, 19, 29 pulser 7, 14, 23 power amplifier 8, 15, 24 preamplifier / receiver 9 oscilloscope 10 , 17,26 Magnetic poles 11 Probe 16,25 Analog-to-digital converter 18,27 Probe head 20,30 Computer device 28 Gradient coil

Claims (7)

[Claims] 1. A radio frequency (RF) source having a continuous waveform (CW) RF output, the CW RF output comprising:
A DC gating pulse is supplied to a modulation device / driver (22) connected to a pulser (29), and the resulting RF pulse is connected to a power amplifier (23). A probe head (27) for accommodating a spin system at the center of the magnetic field (26) is connected to an output section of the probe head (27).
A conventional computer device which can be connected to a preamplifier / receiver for obtaining a reference input from a source (12) and whose output can be controlled for timing and performance through an analog-to-digital converter (ADC) (30), and the other input of the probe (27) is connected to a gradient control unit (28) capable of generating a quadrature gradient pulse for addressing the spin-based storage element. And improved logic devices. 2. The resonance radio frequency (FR) source according to claim 1, wherein the source is a general fixed / variable frequency oscillator / synthesizer capable of generating a continuous wave (CW) RF output. Improved logic units. 3. The improved logic device according to claim 1, wherein said power amplifier has a variable computer controlled attenuator at its output and has a pulse shaping function. 4. The improved logic device according to claim 1, wherein said magnetic field is a magnetic field of a permanent magnet, a uniform magnetic field of a superconducting electromagnet, or a fringe magnetic field of a superconducting electromagnet. 5. The improved logic device of claim 1, wherein said spin system is a set of interacting or non-interacting spins -1/2. 6. A spin system having an electron spin resonance (ESR) line width of up to 1 MHz or an electron nuclear double resonance (ENDOR) line width of up to 1 MHz, or a liquid or solid having a line width of up to 1 MHz. 2. The improved logic device of claim 1 wherein the system is a diamagnetic nuclear spin system. 7. The improved logic device of claim 1, wherein said probe head is used as a radio frequency coil for tuning to a resonance frequency.