Network with multiple oscillators

Abstract

The network includes a plurality of oscillators. The network is configured to control the phases of the plurality of oscillators by thermal coupling via a thermal link.

Description

Technical Field

[0001] Statement Regarding Federally Sponsored Research or Development The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 861153.

[0002] The present invention generally relates to a plurality of oscillators.

Summary of the Invention

[0003] According to embodiments, a network, a method, and a computer program product are disclosed.

[0004] According to embodiments, the present invention is embodied as a network comprising a plurality of oscillators. The network is configured to control the phases of the plurality of oscillators by thermal coupling via a thermal link.

[0005] The above summary is not intended to describe every illustrated embodiment or every implementation of the present disclosure.

[0006] The drawings included in this application are incorporated herein and form a part of this specification. The drawings illustrate embodiments of the present disclosure and, together with the specification, serve to explain the principles of the present disclosure. The drawings merely exemplify specific embodiments and do not limit the present disclosure.

Brief Description of the Drawings

[0007]

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DETAILED DESCRIPTION OF THE INVENTION

[0008] Although the present invention is suitable for various modifications and alternative forms, its details are shown in the drawings as examples and will be described in detail. However, it should be understood that there is no intention to limit the present invention to the specific embodiments described. On the contrary, it is intended to include all modifications, equivalents, and alternatives within the scope of the present invention.

[0009] The present invention generally relates to a plurality of oscillators.

[0010] Such a network may be embodied as oscillatory neural networks (ONNs) and can be used as a hardware implementation form of neuromorphic computing. By using oscillatory neural networks, a neural network can be formed in which information is encoded in the frequency or phase of the oscillators. The coupling elements between individual oscillators may be used for signal processing similar to synaptic functions.

[0011] Such a network of coupled oscillators can perform classification and optimization tasks and can be used as a hardware accelerator for the first layer filters of a convolutional neural network.

[0012] One embodiment uses a relaxation oscillator of VO2 resistors.

[0013] Oscillatory neural networks may offer advantages in terms of robustness, speed, and power efficiency and may be used, in particular, as input filters for feature detection in image recognition.

[0014] Therefore, advanced solutions for such networks are needed.

[0015] According to one aspect, the present invention is embodied as a network comprising a plurality of oscillators. The network is configured to control the phases of the plurality of oscillators by thermal coupling via a thermal link.

[0016] Such a network can offer advantages in terms of energy efficiency since the heat dissipation of the oscillator elements is used to control the phase.

[0017] Furthermore, such a network can offer advantages in terms of area efficiency and ease of manufacture since the thermal coupling can be implemented without additional circuitry such as coupling capacitors or coupling inductors. In particular, electrical capacitors require significantly more space compared to the case where the thermal coupling is arranged.

[0018] According to an embodiment, the thermal link for phase control can enable a faster and higher density oscillatory network with lower power consumption and higher operating speed.

[0019] According to an embodiment, the thermal coupling includes anti-phase coupling. According to an embodiment, the thermal coupling includes in-phase coupling.

[0020] In such a network with positive and negative thermal couplings, the expansion of the application range is promoted.

[0021] According to an embodiment, the network includes a plurality of electrical links for electrically coupling a plurality of oscillators.

[0022] According to an embodiment, the network may be a neural network, and the plurality of oscillators form an oscillatory neural network. The neural network can be, in particular, a hardware implementation form of an artificial neural network.

[0023] According to an embodiment, the oscillator is embodied as a relaxation oscillator. Each oscillator of the plurality of oscillators may include a self-heating solid-state phase change device, and the solid-state phase change device includes a phase change material having a first phase state and a second phase state. The first phase state may be a low-resistance state, and the second phase state may be a high-resistance state. In particular, the first phase state may be a metallic state, and the second phase state may be an insulating state.

[0024] Such types of relaxation oscillators facilitate high-density integration of the network.

[0025] According to an embodiment, the plurality of oscillators include a first oscillator having a first series arrangement of a first self-heating phase change device and a first series resistor, and a second oscillator having a second series arrangement of a second self-heating phase change device and a second series resistor. By thermally coupling the first series resistor to the second self-heating phase change device, a unidirectional thermal coupling can be realized between the first oscillator and the second oscillator.

[0026] According to an embodiment, the network further includes one or more thermal waveguides for promoting thermal coupling.

[0027] According to an embodiment, the network further includes one or more thermal separation structures etched on a substrate of the network, and the one or more thermal separation structures are configured to insulate heat between two or more of the plurality of oscillators.

[0028] According to an embodiment, the series resistor can be implemented as a transistor, a memristor, or any resistive element. According to an embodiment, the device may include an electrical coupling element (memristor) in addition to the thermal link.

[0029] Such a network with unidirectional coupling provides highly flexible advanced applications.

[0030] According to an embodiment, the network is configured to perform adaptive thermal coupling between two or more of the plurality of oscillators by adapting the oscillation frequencies of one or more of the plurality of oscillators, thereby changing the thermal coupling mode. According to an embodiment, the thermal coupling mode may include bidirectional, unidirectional, or non-coupling or a combination thereof. According to an embodiment, adapting the oscillation frequency may include changing one or more parameters of the electrical components of the network.

[0031] Such a network with adaptive thermal coupling provides highly flexible advanced applications.

[0032] According to an embodiment, one or more of the plurality of oscillators include two or more variable resistors, and only one of the two or more variable resistors is thermally coupled to another of the plurality of oscillators. This enables further applications. In particular, as a result of keeping the total resistance of the variable resistor constant, it may be realized that the electrical characteristics of the network or circuit do not change, but the coupling between the oscillators may still be adjusted.

[0033] According to an embodiment, a method for operating a network including a plurality of oscillators is provided. The method includes controlling the phases of the plurality of oscillators by thermal coupling via a thermal link.

[0034] According to an embodiment, a computer program product for operating a network including a plurality of oscillators and a plurality of thermal links is provided. The computer program product includes a computer-readable storage medium in which program instructions are embodied, and the program instructions are executable by the network to perform a method including controlling the phases of the plurality of oscillators by thermal coupling via a thermal link.

[0035] Hereinafter, embodiments of the present invention will be described in more detail by way of illustrative and non-limiting examples with reference to the accompanying drawings.

[0036] Referring to FIGS. 1 to 10, some schematic aspects and terms of embodiments of the present invention are described.

[0037] A thermal wave is a time-varying temperature field around a heating element whose temperature varies periodically.

[0038] The thermal wave changes sign at a distance of about 2,356η, which is a normalized distance, where

Equation

[0039] In the above equation, α means the thermal diffusivity of each material through which the thermal wave propagates, such as the thermal diffusivity of the substrate of the network. The angular frequency ω of the thermal wave is 2πf, where f is the normal frequency in Hz units.

[0040] According to an embodiment, both the coupling and anti-coupling between the oscillators of the network can be realized according to the coupling material, the frequency of the thermal wave, and the distance between the respective elements.

[0041] FIG. 1 shows a network 100 according to an embodiment of the present invention. The network 100 includes a first oscillator 110 and a second oscillator 120. The first oscillator 110 and the second oscillator 120 can be embodied as relaxation oscillators in particular. The first oscillator 110 includes an oscillation element 111, and the second oscillator 120 includes an oscillation element 121. The oscillation element 111 and the oscillation element 121 may be elements whose current-voltage diagram resembles an s-shape in particular. According to an embodiment, the oscillation element 111 and the oscillation element 121 are embodied as self-heating solid-state phase change devices. The solid-state phase change device includes a phase change material having a first phase state and a second phase state. The first phase state may be a metallic state according to an embodiment, and the second phase state may be an insulating state according to an embodiment. The solid-state phase change material may be, for example, VO2, V4O7, V6O11, V2O3, V6O13, V5O9, VO, V8O15, NbO2, Ti2O3, LaCoO3, Ti3O5, SmNiO3, NdNiO3, PrNiO3, or Fe3O4.

[0042] The first oscillator 110 includes a series resistor or resistance element 112 arranged in series with respect to the oscillation element 111. The second oscillator 120 includes a series resistor 122 arranged in series with respect to the oscillation element 121. The first oscillator 110 may further include a capacitor 113 arranged in parallel with respect to the series resistor 112. The second oscillator 120 may further include a capacitor 123 arranged in parallel with respect to the series resistor 122. According to an embodiment, the capacitor may be in parallel with respect to the oscillation element, and thus the oscillation element and the capacitor may form a parallel arrangement. Further, the resistance element may be present in series with respect to this parallel arrangement. The first oscillator 110 receives an input voltage V in1 and the second oscillator 120 receives an input voltage V in2 . The input voltage V in1 and the input voltage V in2 are embodied as DC voltages.

[0043] Network 100 is configured to control the phases of the first oscillator 110 and the second oscillator 120 by thermal coupling via the thermal link 130. The thermal link 130 can be implemented in several different ways depending on the embodiment. According to some embodiments, the thermal link 130 may be configured such that an anti-phase coupling is realized between the first oscillator 110 and the second oscillator 120. According to an embodiment, the thermal link 130 may be configured such that an in-phase coupling is realized between the first oscillator 110 and the second oscillator 120. Each coupling mode between the first oscillator 110 and the second oscillator 120 can be realized in various ways depending on (dependent on) in particular the respective coupling materials, the frequency of the heat wave, and the distance between the respective elements related to the thermal coupling.

[0044] Optionally, network 100 may comprise an electrical link 140 for electrically coupling the first oscillator 110 and the second oscillator 120. This is shown by a dashed line.

[0045] Optionally, network 100 may be configured as a neural network in particular. According to such an embodiment, the oscillator 110, the oscillator 120, and a plurality of further oscillators may form a vibrating neural network.

[0046] FIG. 2 shows a network 200 according to an embodiment of the present invention. Network 200 comprises a first oscillator 210 and a second oscillator 220. The first oscillator 210 and the second oscillator 220 are embodied as relaxation oscillators comprising self-heating solid phase change devices. For ease of illustration, only the respective self-heating solid phase change devices 211 and 221 of the first oscillator 210 and the second oscillator 220 are shown.

[0047] The first oscillator 210 and the second oscillator 220 are arranged at a pre-defined radial distance r relative to each other. Each of the pre-defined radial distances r from the first oscillator 210 is shown by the horizontal axis 240 in FIG. 2. More specifically, the second oscillator 220 is arranged at a distance d of approximately 2.356η from the first oscillator 210. As a result, thermal negative coupling, in other words inverse-phase thermal coupling, occurs. The thermal coupling can be specifically realized, for example, by thermal substrate coupling through a common substrate on which the first oscillator 210 and the second oscillator 220 are arranged. According to an embodiment, at a distance d of approximately 2.356η, the phase delay of the thermal wave through the substrate is

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[0048] Figure 3 shows a network 300 according to an embodiment of the present invention. According to the embodiment of FIG. 3, several oscillators can be arranged within the negative coupling region of the first oscillator 1. More specifically, the network 300 includes a plurality of n oscillators represented as oscillator 1, oscillator 2, …, oscillator n. The n oscillators are embodied as relaxation oscillators including self-heating solid phase change devices. For ease of illustration, only the self-heating solid phase change devices 311, 321, …, 3n1 of each of the n oscillators are shown.

[0049] Oscillator 2 and further oscillators 3, …, oscillator n are arranged at a predefined radial distance r with respect to oscillator 1. This is shown by the horizontal axis 340. More specifically, oscillator 2 and further oscillators 3, …, oscillator n are each arranged at a radial distance of approximately 2.356η from oscillator 1. As a result, thermal negative coupling, in other words, inverse-phase thermal coupling occurs. At a distance d of approximately 2.356η, the phase delay of the thermal wave passing through the substrate is

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[0050] Each of the time Δt between the peak heat dissipation of oscillator 1 (reference) and the heat propagation to the surroundings through the substrate is shown by the horizontal axis 341 in FIG. 3, and the corresponding phase delay

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[0051] FIG. 4 shows a network 400 according to a further embodiment of the present invention. The network 400 includes three oscillators 410, 420, and 430 that form an equilateral triangle configuration. In this way, all three oscillators 410, 420, and 430 can be separated from each other while maintaining a distance of approximately 2.356η. Therefore, according to the embodiment, it is possible to negatively couple all three oscillators 410, 420, and 430 to each other.

[0052] FIG. 5 shows a network 500 according to a further embodiment of the present invention. The network 500 includes a first oscillator 510 and a second oscillator 520. The first oscillator 510 includes an oscillation element 511, and the second oscillator 520 includes an oscillation element 521, and they can be embodied as self-heating solid-phase change devices.

[0053] The first oscillator 510 includes a series resistor 512 arranged in series with respect to the oscillation element 511. The second oscillator 520 includes a series resistor 522 arranged in series with respect to the oscillation element 521. The first oscillator 510 may further include a capacitor 513 arranged in parallel with respect to the series resistor 512. The second oscillator 520 may further include a capacitor 523 arranged in parallel with respect to the series resistor 522. According to an embodiment (not shown), the capacitor may be in parallel with respect to the oscillation element, and thus the oscillation element and the capacitor may form a parallel arrangement. Further, the resistive element may be present in series with respect to this parallel arrangement.

[0054] The first series resistor 512 is disposed adjacent to or in proximity to the oscillation element 521, thereby realizing thermal coupling with the oscillation element 521. The heat dissipated by the series resistor 512 of the oscillator 510 affects the oscillator 520, but the series resistor 512 itself is not affected by the oscillator 520 because its resistance is substantially constant with respect to temperature. Further, the oscillation elements 511 and 521 are disposed at a distance that is too large for them to thermally affect each other. As a result of such an arrangement, unidirectional thermal coupling can be realized between the first oscillator 510 and the second oscillator 520.

[0055] FIG. 6 shows a network 600 according to a further embodiment of the present invention. The network 600 includes a first oscillator 610 and a second oscillator 620. The first oscillator 610 includes an oscillation element 611, and the second oscillator 620 includes an oscillation element 621, which can be embodied as a self-heating solid phase change device. For ease of illustration, the first oscillation element 611 and the second oscillation element 621 are shown in a simplified form. The first oscillator 610 and the second oscillator 620 are integrated on a common substrate 630 such as, for example, a Si substrate or a III-V substrate. The network 600 includes a thermal waveguide 640 between the first oscillator 610 and the second oscillator 620. The thermal waveguide 640 can be integrated into the substrate 630. The thermal waveguide 640 is composed of a material having a thermal diffusivity α th substrate different from the thermal diffusivity α th waveguide of the substrate. By using this, the propagation of thermal fluctuations between the respective oscillation elements of the first oscillator 610 and the second oscillator 620 can be manipulated or adapted. The corresponding thermal fluctuations propagating through the substrate are shown by the dashed pattern 631, while the corresponding fluctuations propagating through the thermal waveguide 640 are shown by the dotted pattern 641. More specifically, each of the thermal fluctuations 631 and 641 has a phase of

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[0056] In the example of FIG. 6, the thermal waveguide 640 is made of a material having a thermal diffusivity α th substrate greater than α th waveguide Thus, η th waveguide is greater than η substrate by a greater amount.

[0057] Therefore, the wavelength of the heat wave 641 in the thermal waveguide 640 is longer than the wavelength of the heat wave 631 in the substrate 630.

[0058] FIG. 7 shows a network 700 according to a further embodiment of the present invention. The network 700 includes a first oscillator 710 and a second oscillator 720. The first oscillator 710 includes an oscillation element 711, and the second oscillator 720 includes an oscillation element 721, which can be embodied as a self-heating solid-phase change device. The first oscillator 710 and the second oscillator 720 are integrated on a common substrate 730 such as, for example, a Si substrate or a III-V substrate. The network 700 includes a trench 735 etched in the substrate 730 of the network as a thermal isolation structure. The trench 735 is configured to insulate heat between the first oscillator 710 and the second oscillator 720. By filling the trench 735 with a material having a low thermal diffusivity α, the propagation of heat waves may be inhibited to achieve non-coupling. Heat dissipation from portions of the network where external circuit elements or thermal coupling are not desired may cause parasitic effects and may have a disruptive effect on the network. By doing so, further high-density packaging becomes possible.

[0059] The corresponding waves propagating through the substrate are indicated by the dashed pattern 731.

[0060] According to one embodiment, as shown in FIG. 5, the series resistor 512, which is a fixed resistor connected as such, is replaced with two or more variable resistors that are either in parallel or in series, and only one of them is coupled to the second oscillator, whereby the coupling strength of the thermal coupling can be manipulated. Such a configuration is shown with reference to FIG. 8. According to the embodiment, the variable resistor can be implemented or embodied by a transistor, a memristor, or any other element whose resistance can be adjusted.

[0061] FIG. 8 shows a network 800 according to a further embodiment of the present invention. The network 800 includes a first oscillator 810 and a second oscillator 820. The first oscillator 810 includes an oscillation element 811, and the second oscillator 820 includes an oscillation element 821, which can be embodied as a self-heating solid-phase change device.

[0062] The first oscillator 810 includes a series resistor 812 and a series resistor 813 that are arranged in series with respect to the oscillation element 811. The first oscillator 810 may further include a capacitor 814 that is arranged in parallel with respect to the series resistor 812. The series resistor 812 and the series resistor 813 are embodied as variable resistors whose resistance can be adjusted.

[0063] By arranging the series resistor 812 adjacent to or in proximity to the oscillation element 821, thermal coupling with the oscillation element 821 is realized. The heat dissipated by the series resistor 812 affects the oscillator 820, but the series resistor 812 itself is not affected by the oscillator 820 because its resistance is substantially constant with respect to temperature. Further, the oscillation element 811 and the oscillation element 821 are arranged at a distance that is too large for them to thermally affect each other.

[0064] In the following, the resistor 812 has a resistance R s1,1 and the resistor 813 has a resistance R s1,2 Let it be assumed. By adjusting both the resistor 812 and the resistor 813 simultaneously, their total resistance R ges1 (R s1,1, R s1,2 ) is kept constant, and the energy dissipated by R ges1 is also kept constant, so it is possible to not change the electrical characteristics of the network or circuit. However, the resistances of resistors R s1,1 and resistor R s1,2 Each energy dissipation increases on one hand and decreases on the other hand. Only one of the two resistors, in this example R s1,1 is coupled to the oscillation element 821, so the influence of the oscillator 810 on the oscillator 820 can be adjusted. Furthermore, by dividing the series resistor R ges2 of the oscillator 820, the influence of the oscillator 820 on the oscillator 810 can also be adjusted (the series resistor of the oscillator 820 is not shown in FIG. 8).

[0065] According to an embodiment, the following coupling strength configurations can generally be realized.

[0066] Focusing on the coupling between the two oscillators, a configuration can be selected. For example, a unidirectional coupling in which the oscillator 810 affects the oscillator 820, a unidirectional coupling in which the oscillator 820 affects the oscillator 810, a bidirectional coupling in which the oscillator 810 affects the oscillator 820 with a first coupling strength a and the oscillator 820 affects the oscillator 810 with a second coupling strength b, or non-coupling, or one or more of combinations thereof can be selected.

[0067] According to an embodiment, the series resistor R ges of the oscillator can be divided into two resistors R s1,1 and R s1,2 arranged in parallel or in series. The arrangement may be such that the distances of one of the two resistors to the adjacent oscillation elements are different. Even if the total resistance is set, the ratio between the two resistors may be independently varied. By doing so, variable thermal coupling can be realized.

[0068] According to an embodiment, the variable resistor can be implemented by a resistive element including a transistor or a memristor.

[0069] Figures 9(a) to 9(c) show a network 900 configured to perform adaptive thermal coupling between a first oscillator 910 and a second oscillator 920. Network 900 corresponds to network 600 shown in FIG. 6 and includes a first oscillator 910 and a second oscillator 920. The first oscillator 910 includes an oscillation element 911, and the second oscillator 920 includes an oscillation element 921, which can be embodied as a self-heating solid-phase change device. For ease of illustration, the second oscillation element 921 is shown in a simplified form. The first oscillator 910 and the second oscillator 920 are integrated on a common substrate 930 such as, for example, an Si substrate or a III-V substrate. Network 900 includes a thermal waveguide 940 between the first oscillator 910 and the second oscillator 920. The thermal waveguide 940 can be integrated into the substrate 930. The thermal waveguide 940 is composed of a material having a thermal diffusivity α th substrate different from the thermal diffusivity α th waveguide of the substrate. The corresponding wave propagating through the substrate is shown by the dashed pattern 931, while the corresponding wave propagating through the thermal waveguide 940 is shown by the dotted pattern 941. More specifically, only the waves 931 and 941 when the phases are

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[0070] The first oscillator 910 and the second oscillator 920 are arranged at a certain distance d from each other.

[0071] Network 900 is configured to perform adaptive thermal coupling by changing each thermal coupling mode, particularly by adapting the oscillation frequencies of one or more oscillators of network 900.

[0072] More specifically, FIG. 9(a) shows negative coupling, FIG. 9(b) shows positive coupling, and FIG. 9(c) shows non-coupling.

[0073] For example, modes of thermal coupling such as positive coupling (driving the oscillator

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[0074] Referring now to FIG. 9(a), negative coupling can be achieved by selecting a distance d such that

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[0075] Referring to FIG. 9(b), the positive coupling can be achieved by selecting such that the angular frequency ω1 of oscillator 910 is less than the frequency ω of the corresponding negative coupling (i.e., ω1 < ω * ). *

[0076] Referring to FIG. 9(c), the non - coupling can be achieved by selecting such that the angular frequency ω2 of oscillator 910 is greater than the frequency ω of the corresponding negative coupling (i.e., ω2 > ω * ). *

[0077] Thus, the amplitude of the thermal fluctuations of the second oscillator 920 becomes very low.

[0078] According to an embodiment, instead of operating the two oscillators at the same frequency, they may be coupled at different or the same harmonics (integer multiples of the frequency f).

[0079] FIG. 10 shows the method steps of a method according to an embodiment of the present invention. For the method steps, reference is made in particular to the network 900 of FIG. 9.

[0080] In step 1010, the method starts.

[0081] In step 1020, the control logic of the network 900 checks in which coupling mode to operate and obtains the desired coupling mode.

[0082] In step 1030, the frequencies of the respective oscillators are adapted to operate in the desired coupling mode.

[0083] Thereafter, in step 1040, the network 900 controls the phase of the oscillators by thermal coupling via the thermal link.

[0084] ​​The present invention may be a system, a method, a computer program product, or a combination thereof. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions for causing a processor to perform aspects of the present invention.

[0085] The present invention may be embodied, in particular, as a computer program product for operating a network such as the networks 100 to 900 described above.

[0086] A computer-readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution device. The computer-readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a punched card, a mechanically encoded device having recorded instructions such as a groove or raised structure in a surface, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium should not be construed as being a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., an optical pulse passing through an optical fiber cable), or an electrical signal transmitted through a wire.

[0087] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to respective computing / processing devices, or can be downloaded from an external computer or an external storage device via a network such as, for example, the Internet, a local area network, a wide area network, or a wireless network, or a combination thereof. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, or edge servers, or a combination thereof. The network adapter card or network interface of each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions for storage in a computer-readable storage medium within each respective computing / processing device.

[0088] The computer-readable program instructions for performing the operations of the present invention may be source code or object code written in any combination of one or more programming languages, including assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or object-oriented programming languages such as Smalltalk, C++, and conventional procedural programming languages such as the "C" programming language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider). In some embodiments, an electronic circuit, including, for example, a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may execute the computer-readable program instructions by utilizing the state information of the computer-readable program instructions to personalize the electronic circuit.

[0089] Aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0090] Such computer-readable program instructions may be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in one or more blocks of a flowchart, a block diagram, or both. Such computer-readable program instructions may also be stored in a computer-readable storage medium that includes instructions for implementing the aspects of the functions / acts specified in one or more blocks of a flowchart, a block diagram, or both, the computer-readable storage medium being a product that, when stored in a computer-programmable data processing apparatus or other device or combination thereof, can be instructed to function in a particular manner.

[0091] Computer-readable program instructions may also be loaded onto a computer, other programmable apparatus, or other device to produce a process that is executed by the computer, such that the instructions, which execute on the computer, other programmable apparatus, or other device, cause the computer, other programmable apparatus, or other device to implement the functions / acts specified in one or more blocks of a flowchart, a block diagram, or both by performing a series of operational steps.

[0092] Flowcharts and block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a part of an instruction that includes one or more executable instructions for implementing a module, segment, or specified logical function. In some alternative implementations, the functions recited in the blocks may occur out of the order recited in the drawings. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order, depending on the functionality involved. It should also be noted that each block of a block diagram or flowchart diagram, or combinations of blocks in a block diagram or flowchart diagram or both, can be implemented by a dedicated hardware-based system that performs the specified function or operation, or a combination of dedicated hardware and computer instructions.

[0093] The description of various embodiments of the present invention has been presented for purposes of illustration, but is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the described embodiments. The terms used herein have been chosen to best explain the principles of the embodiments, the practical application, or technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A network comprising a plurality of oscillators, wherein the network is configured to control the phases of the plurality of oscillators by thermal coupling via a thermal link.

2. The network according to claim 1, wherein the thermal coupling includes anti-phase coupling.

3. The network according to claim 1, wherein the thermal coupling includes in-phase coupling.

4. The network according to claim 1, wherein the network comprises a plurality of electrical links for electrically coupling the plurality of oscillators.

5. The network is a neural network, The network according to claim 1, wherein the plurality of oscillators form an oscillatory neural network.

6. The network according to claim 1, wherein the plurality of oscillators include a first oscillator and a second oscillator, and the second oscillator is disposed within an anti-phase coupling region of the first oscillator.

7. The network according to claim 1, wherein the plurality of oscillators include a first oscillator, a second oscillator, and a third oscillator, and the first oscillator, the second oscillator, and the third oscillator are all disposed within anti-phase coupling regions with respect to each other.

8. The network according to claim 1, wherein each oscillator of the plurality of oscillators is embodied as a relaxation oscillator.

9. The network according to claim 1, wherein each oscillator of the plurality of oscillators comprises a self-heating solid phase change device, and the solid phase change device comprises a phase change material having a first phase state and a second phase state.

10. The network according to claim 9, wherein the first phase state is a low resistance state and the second phase state is a high resistance state.

11. The network according to claim 9, wherein the solid phase change material is selected from the group consisting of VO2, V4O7, V6O11, V2O3, V6O13, V5O9, VO, V8O15, NbO2, Ti2O3, LaCoO3, Ti3O5, SmNiO3, NdNiO3, PrNiO3, and Fe3O4.

12. The plurality of oscillators includes a first oscillator having a first series arrangement of a first self-heating phase change device and a first series resistor, and a second oscillator having a second series arrangement of a second self-heating phase change device and a second series resistor, wherein the first series resistor is thermally coupled to the second self-heating phase change device, thereby realizing unidirectional thermal coupling between the first oscillator and the second oscillator. The network according to claim 9.

13. The network according to claim 1, further comprising one or more heat waveguides for promoting the thermal coupling.

14. The network according to claim 1, further comprising one or more thermal separation structures etched on a substrate of the network, wherein the one or more thermal separation structures are configured to thermally insulate between two or more of the plurality of oscillators.

15. The network according to claim 1 is configured to perform adaptive thermal coupling between two or more of the plurality of oscillators by adapting the oscillation frequencies of one or more of the plurality of oscillators, thereby changing the thermal coupling mode.

16. The network according to claim 15, wherein adapting the oscillation frequency includes changing one or more parameters of electrical components of the network.

17. The network according to claim 15, wherein adapting the oscillation frequency includes changing a local temperature or an overall temperature of a substrate of the network.

18. One or more of the plurality of oscillators includes two or more variable resistors, and only one of the two or more variable resistors is thermally coupled to another one of the plurality of oscillators. The network according to claim 1.

19. A method for operating a network including a plurality of oscillators, the method including controlling phases of the plurality of oscillators by thermal coupling via a thermal link.

20. A computer program product for operating a network, the network including a plurality of oscillators and a plurality of thermal links, the computer program product including a computer-readable storage medium having program instructions embodied thereon, the program instructions being A computer program product, executable by the network, for performing a method that includes controlling the phases of the plurality of oscillators by thermal coupling through the thermal link.

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