Abstract
A novel model to be applied to nextgeneration accelerators, Ising machines, is formulated on the basis of the phasefield model of the phaseseparation structure of a diblock polymer. Recently, Ising machines including quantum annealing machines, attract overwhelming attention as a technology that opens up future possibilities. On the other hand, the phasefield model has demonstrated its high performance in material development, though it takes a long time to achieve equilibrium. Although the convergence time problem might be solved by the nextgeneration accelerators, no solution has been proposed. In this study, we show the calculation of the phaseseparation structure of a diblock polymer as the equilibrium state using phasefield model by an actual Ising machine. The proposed new model brings remarkable acceleration in obtaining the phaseseparation structure. Our model can be solved on a largescale quantum annealing machine. The significant acceleration of the phasefield simulation by the quantum technique pushes the material development to the next stage.
Introduction
Diblock polymers are a widely used material for structures^{1}. The microstructure of a diblock polymer changes depending on the synthetic conditions. The process of the change in microstructure is spinodal decomposition, and various phaseseparated structures, such as lamellar, cubic, hexagonal, and gyroid structures, can be obtained^{2}. Since this material structure has a strong influence on mechanical properties^{3}, it is very important to predict which structure will be obtained experimentally.
To date, several methods have been developed to analyze the equilibrium state of diblock polymers, such as the molecular dynamics^{4} Monte Carlo method^{5}, the selfconsistent field theory^{6} and the phasefield model^{7,8}. The phasefield model is a continuum model that expresses the interface with a smooth function using a variable called the order parameter. This model has the advantage of being free from solving complicated boundary value problems. The governing equation can be derived in a relatively simple form. Hence, it is widely used to reproduce various material structures^{1,9,10,11,12,13,14,15,16}. The governing equation of the phasefield model is formulated by variation of the energy functional. However, conventional analysis sometimes takes a very long time to obtain an equilibrium state, which is a problem when a largescale simulation is required. Hence, various schemes have been proposed to solve this problem^{17,18,19}, which is the key to accelerating material development.
On the other hand, nextgeneration accelerators including quantum computers are steadily developing. In particular, quantum annealing machines^{20,21,22,23} can search for the minimum value of the objective function at high speed. They are often applied to combinational optimization problems involving the objective functions of the target. If the objective function can be replaced with energy expressing the target phenomenon, quantum acceleration of finding of equilibrium state acquisition can be expected by a physics simulation^{24,25,26,27}.
In this study, we propose an objective function for exploring the phaseseparated structure of diblock polymers by annealing, with an eye toward the use of quantum annealing. On the basis of the obtained results, we confirm the tendency of the microstructure and the simulation performance by comparison with the phasefield simulation. The approach is based on the use of a global optimization metaheuristic algorithm, called simulated annealing, to directly minimize the Helmholtz free energy instead of minimizing it analytically and then solving the resulting nonlinear, partial differential equation, i.e., the governing equation of the phasefield model. In this paper, we illustrate the use of simulated annealing in the solution of the phasefield model by applying it to the formation of a microstructure in a diblock polymer.
First, we review the results of the conventional analysis method of the phasefield model and propose the Ising model for solving the phasefield model in the following section. Subsequently, we present the calculation results of the newly defined quantity for the Ising model. Ising machines are used as a dedicated accelerator for solving Ising model, and from the simulation by the Ising machine, we find remarkable results, which indicate the effectiveness of the proposed approach. Finally, we conclude with remarks on the possibilities of a much largerscale simulation and on the application of the annealing method to other problems related to continuum mechanics.
To verify the problem of spinodal decomposition for diblock polymers, we carry out conventional phasefield simulations. A phase diagram of the phaseseparated structure in the diblock polymer is shown in Fig. 1^{2}. The phasefield model is composed of the gradient energy, Flory–Huggins interaction energy^{28,29}, and OhtaKawasaki longdistance interaction energy^{30}. The fineness of the phaseseparation structure is controlled by the magnitude of the OhtaKawasaki energy. The governing equation is derived through the Cahn–Hilliard equation^{30} and discretized by the finite difference method following the conventional manner. The mobility \(M\) in the analysis is employed as \(M=1.0\, {\mathrm{s}}^{1}\). The analysis area of \(32 \,\upmu\mathrm{m}\times 32\,\upmu\mathrm{m}\) is discretized into \(64\times 64\) grids under the periodic boundary condition.
The initial distribution is given by random noise around \(f=0.5\), which is shown in Fig. 2a(i). First, we conduct a numerical analysis with the constant of longdistance interaction terms \({c}_{0}\) equal to zero. Figure 2 a(ii) shows the equilibrium state obtained by phasefield analysis. Polymer A is shown in blue, and polymer B is shown in red, being separated into two large phases. These large phases are considered to minimize the surface energy. Next, we change the parameter c_{0} in the longdistance term derived from the OhtaKawasaki energy^{30}. We confirm that the incremental error at the final computational step becomes less than \(1.2\times {10}^{6}\) in all cases. The incremental error is defined as the product of the time increment per step and the maximum increment of the order parameter per step among all the grids. In Fig. 2b, the separation pattern, which is different from that in Fig. 2a, becomes finer with increasing parameter c_{0}, which is considered to be induced by the effect of the longdistance energy term of the OhtaKawasaki energy. Additionally, the phaseseparation structure in Fig. 2a(ii) seems cubic or hexagonal, as in Fig. 1, while that in Fig. 2b(iii) is lamellarlike, as in Fig. 1. The effect becomes more significant as the effect of the OhtaKawasaki energy increases. Both simulations take approximately 5960 s.
We performed a new phasefield simulation using an Ising machine which solves one of the formalized combinatorial optimization problems, i.e., quadratic unconstrained binary optimization (QUBO). QUBO uses a set of binary states. The objective function, called the Hamiltonian, is composed only of the quadratic polynomials of the states. One of the advantages of Ising machines is that once the problem is well formalized as a QUBOstyle Hamiltonian, Ising machines can be used to solve the problem without paying attention to the details of numerical calculations, such as the discretization error of finite time steps and the solver implementation method.
Our proposed method formalizes the problem of spinodal decomposition for diblock polymers into the QUBOstyle Hamiltonian. This Hamiltonian is composed of four terms that represent different physical behaviors of diblock polymers: the sum amount conservation term, the Flory–Huggins interaction energy term, the gradient energy term and the OhtaKawasaki longdistance interaction energy term. The strength of the impact on each of the four terms is controlled by the parameters \({\alpha }_{F}, {\alpha }_{I}, {\alpha }_{A}\) and \({\alpha }_{OK}\), respectively, and the parameter \(f\) determines the fraction of monomer. The strength of the OhtaKawasaki energy term controls the fineness of the phaseseparation structure. Note that Ising machines efficiently find the global minimum solution of a given Hamiltonian without becoming trapped at a local minimum solution. Thus, if a desired final state of a phasefield model is a local minimum free energy near the initial state, Ising machines may not be able to obtain the same results as the conventional method. Therefore, we report a new method of the phasefield model whose final simulation state must be the global minimum free energy.
To perform phasefield simulation by the Ising machine, we transform the phasefield model into a QUBO model. We set a twodimensional calculation area and divide it into grids. We assign four binary variables to any ith grid point \({S}_{i}\):
and we express the order parameter of the ith grid point as \({\sum }_{0\le k<4}{a}_{4i+k}\). Since \({a}_{4i+k}\in \{\mathrm{0,1}\}\), the value range of \({S}_{i}\) is from 0 to 4 in this case. If we assign more binary variables to each grid, the resolution of the result is expected to increase, and as a result, the total number of required binary variables also increases.
First, we conduct numerical simulation cases with and without OhtaKawasaki energy. We set the material properties in the analysis as follows: \({\alpha }_{I}=20.0, {\alpha }_{A}=5.0,{\alpha }_{OK}=0.0/0.4\) and \(f=0.5\). Figure 3 shows the numerical analysis results of \({S}_{i}\). Clearly, the phases of polymer A and polymer B, shown in white and black, respectively, are separated into two large phases without OhtaKawasaki energy, as shown in Fig. 3a, while the composition of polymers A and B with OhtaKawasaki energy equilibrates with a finer pattern, as shown in Fig. 3b.
Figure 4 shows the emulation process of the annealing optimization in other cases with and without OhtaKawasaki energy. Note that this figure shows the results obtained when the Ising machine is interrupted before the process has finished and does not directly correspond to the physical time in the conventional method. We set \({\alpha }_{I}=20.0, {\alpha }_{A}=5.0,{ \alpha }_{OK}=0.0/0.5\) and \(f=0.3.\) The simulation result without OhtaKawasaki energy (Fig. 4a(iv)) shows a larger pattern than the one with OhtaKawasaki energy (Fig. 4b(iv)). With the proposed Ising models, the simulation takes only 1 s.
To show the exact execution times of the two methods, we studied how the energy decreases with time in the conventional method and our new method in one simulation as an example. In Fig. 5a, we show the time evolution of the free energy of one randomly selected simulation using the conventional method. This figure shows that the simulation using the conventional method converges in about 4000 s (64 × 64 cells). Correspondingly, we performed some simulations using our new method with different timeout times. In Fig. 5b–d, we show the minimum energy that was found in less than a specified time. This figure shows that the simulations using Ising machines reach the minimum energy in about 0.8 s (32 × 32 cells), 1.5 s (40 × 40 cells), and 2.5 s (48 × 48 cells), which is very fast compared with the conventional method.
Finally, we carry out inclusively largescale parametric analyses. Figure 6a shows the numerical analysis results in the case of fraction rate \(f=0.5\), and Fig. 6b shows the case of \(f=0.3\).
When you look at the phase diagram in Fig. 1, the case of \(f=0.5\) shows only lamellar patterns, indicating that the parametric study using the defined Hamiltonian outputs physically correct results. In the case of \(f=0.3\), hexagonal or cubic patterns should be observed from the phase diagram of Fig. 1, and it seems that the dotted pattern or the striped patterns may change depending on the viewing direction of these patterns because of the carrying out of twodimensional calculations. Similar to the conventional phasefield analysis results, the characteristic length of the pattern seems to be shortened; thus, it makes sense that the pattern becomes finer as the longdistance interaction becomes stronger with increasing OhtaKawasaki energy.
When the coefficient of the gradient energy term becomes large, the parameter corresponding to the diffusion coefficient increases. This parameter change does not appear in the phase diagram in Fig. 1. The phase diagram should generally be created with the same material at a constant environmental temperature. However, the above outcome makes sense because the larger the gradient energy becomes, the larger the structure tends to be (the farther the material is distributed) in Fig. 6a,b. Additionally, in the region where the interaction energy is small, the pattern tends to be disordered, which is consistent with the phase diagram.
As shown in Fig. 6, the results are quite similar to those obtained by the conventional method, which means that the proposed modeling based on the Ising model is quite useful.
Note that there is no strict symmetry in the OhtaKawasaki term, but essentially, in the case of \(f=0.7\) and \(f=0.3\), the colors are simply swapped. If \({\alpha }_{OK}\) equals zero, there is strict symmetry; thus, the same pattern with completely inverted colors will appear. Additionally, since the Hamiltonian has symmetry when rotated 90 degrees about the xy axes, the direction of the lamellar structure appears randomly.
In terms of accuracy evaluation, the new QUBO model is not exactly the same as the conventional one and, thus, does not shared exactly the same parameters as the conventional method; making a direct comparison with the same model parameters is impossible. Instead of comparing the accuracy between the two methods, we evaluate errors due to the discretization of continuous order parameters in a simulation. In our QUBO model, the order parameters \({S}_{i}\) was discretized to (0, 1, 2, 3, 4). We now introduce a continuous version of our QUBO model, called continuousQUBO, that is, the term \({\sum }_{k}{a}_{4i+k}\) in Eqs. (11)–(14) is replaced with continuous variables \({x}_{i}\in \left[\mathrm{0,4}\right]\). Then, the Hamiltonian of continuousQUBO is minimized and the optimal order parameter \({x}_{i}^{*}\) is obtained using the gradient descent method. The error is calculated between the result obtained with the Ising machine, \({S}_{i}^{*}\), and the result of continuousQUBO, \({x}_{i}^{*}\), which is considered the true value. This enables us to calculate the accuracy of the same model parameters. Figure 7 shows (a) one of the results obtained with the Ising machine, \({S}_{i}^{*}\), (b) the corresponding optimal order parameter of continuousQUBO, \({x}_{i}^{*}\), and (c) the difference between the two plots. In this result, the mean error per cell \({\langle \left{{S}_{i}^{*}x}_{i}^{*}\right\rangle }_{i}\) is about 0.018, which is sufficiently smaller than 1.0, which is the discretization size of the order parameter \({S}_{i}^{*}\).
In this study, we proposed a novel method to solve the phasefield model by the objective function for exploring the phaseseparated structure of diblock polymers by an Ising machine, with an eye toward the use of quantum annealer. We confirmed the tendency from the obtained results and the performance by comparing them with the phasefield simulation. The approach involves the use of a global optimization metaheuristic algorithm, called simulated annealing, to directly minimize the Helmholtz free energy instead of minimizing it analytically and then solving the resulting nonlinear, partial differential equation, i.e., the governing equation of the phasefield model. As a result, we obtained the following:

1.
The results obtained by Ising machine showed the same tendency as the results obtained from the conventional phasefield analysis.

2.
The obtained results were consistent with the phase diagram.

3.
The analysis time was shortened to the extent that highspeed comprehensive analysis becomes possible.
The proposed modeling based on the Ising model has been shown to be very useful. In the future, we will address the following remaining issues for the practical use of this method. First, we will investigate the usefulness of the intermediate results obtained with an Ising machine, which may correspond to the nonequilibrium time history of the distribution obtained by the conventional method. Second, as the number of bits that Ising machines can handle increases, it will be possible to apply our method to the 3D domain. Third, as noted above, a direct comparison with the same model parameters is not yet possible. We will clarify the relationship between the parameters of our model and these of the conventional model by introducing correction terms using machine learning methods.
This scheme on how to discretize the continuum variable and formulate the QUBO will help in solving the other problems related to continuum mechanics.
Methods
Theory of the phasefield model
The phasefield model for spinodal decomposition is introduced. First, the Cahn–Hilliard equation^{31} can be written as follows:
where \(c\) is the concentration of a phase, which is the order parameter in the phasefield model, \(F\) is the free energy functional and \(M\) is the mobility. Here, \(F\) is formulated with consideration of the longdistance interaction as follows:
where \({F}_{\mathrm{grad}}\) is the gradient energy, \({F}_{\mathrm{chem}}\) is the chemical potential and \({F}_{\mathrm{long}}\) is the longdistance interaction. These variables are defined as
where the variables with indices \(a\) and \(b\) denote the quantities of phase \(a\) and phase \(b\), respectively. Additionally, \(c\) is the concentration, \(\kappa\) is the diffusion coefficient, and \({\varvec{x}}\) and \({{\varvec{x}}}^{^{\prime}}\) are the position vectors. Moreover, \(\chi\) is the interaction coefficient (Flory), and \(A\) is the coefficient of the longdistance interaction. These coefficients are defined by \(\kappa =1/(12r(1f))\) and \(A={c}_{0}/(2{N}^{2}d{s}^{2}{f}^{2}(1f{)}^{2})\), with the numerical constant \({c}_{0}\) defined as in a previous work^{27}, the ratio of phase b denoted by \(f\), the number of segments denoted by \(N\) and the length of the segment denoted by \(ds\). Here, we can see that \({c}_{0}\) is the constant associated with the longdistance interaction term derived from OhtaKawasaki energy. Note that \({c}_{a}+{c}_{b}=1\). The variation in the energy with respect to \({c}_{b}\) can be calculated as
Substituting Eq. (7) into the Cahn–Hilliard Eq. (2) and eliminating the index \(b\), the equation can be reduced as
Here, \(\mu\) is defined as \(\mu \equiv \kappa {\nabla }^{2}c+\chi RT\mathrm{ln}c\), and \(M\) is considered constant. For the implementation of Eq. (8) in a program code, the finite difference method is generally employed. In addition, \(\delta ({\varvec{x}}{{\varvec{x}}}^{^{\prime}})={\nabla }^{2}{\Omega }_{ab}({\varvec{x}}{{\varvec{x}}}^{^{\prime}})\), and \(\delta\) is the Green function, which is calculated through a Fourier transformation.
Calculation by an Ising machine
We conducted the calculations using Fixstars Amplify Annealing Engine (Amplify AE)^{32} with timeout of 1 s. Amplify AE is GPUbased Ising machine that can handle 100,000 bitclass problems.
When solving a problem by using Ising machines, we must design QUBO models of the binary variables. The QUBO model is formulated as
where \(H\) is the Hamiltonian or the energy, \(N\) is the number of binary variables, \({a}_{i}\in \{\mathrm{0,1}\}\) is a binary variable, and \({Q}_{ij}\) denotes the interaction parameters. Ising machines search the values \(\{{a}_{i}\}\) so that the Hamiltonian \(H\) is minimized. The diagonal and offdiagonal elements of \(Q\) represent the strength of bias and quadratic interactions, respectively. Here, it is necessary to set \({Q}_{ij}\) properly depending on the problem.
Hamiltonian
We formulate the Hamiltonian. We construct the whole Hamiltonian \(H\) as a linear combination of the summation preservation term \({H}_{\text{sum}}\), the interaction (internal) energy term \({H}_{int}\), the gradient (adjacent) energy term \({H}_{\text{adj}}\), and the longdistance energy term (the socalled OhtaKawasaki energy) \({H}_{\text{long}}\):
where
The term \({H}_{\mathrm{sum}}\) constrains the total order parameter of space. Equation (11) uses the square constraint because a strict preservation term cannot be used in QUBO models. The constant \({\alpha }_{F}\) controls the strictness of preservation, and the constant \(f\) denotes the target total ratio of the order parameter. The term \({H}_{\mathrm{int}}\) makes the order parameter of each point 0 or 4 to avoid intermediate states as much as possible, with strength \({\alpha }_{I}\). The term \({H}_{\mathrm{adj}}\) controls the strength of adjacent interactions by bringing closer the order parameter of adjacent pairs of the grid points together. \({P}_{\mathrm{adj}}\) denotes the set of all adjacent pairs. The coefficient \({\alpha }_{A}\) is the strength of adjacent interactions. The term \({H}_{\mathrm{long}}\) expresses the OhtaKawasaki energy, and \({g}_{ij}\) is defined as \({g}_{ij}\equiv 1/{r}_{ij}\), with the distance between grids i and j denoted by \({r}_{ij}\). \({P}_{\mathrm{all}}\) denotes the set of all pairs of all grid points.
Multiplying the coefficient of each term by a constant does not influence the simulation results; thus, we set \({\alpha }_{F}\) to 1. In this setting, the whole Hamiltonian contains at most a quadratic term of the variables \(\left\{{a}_{i}\right\}\); therefore, rearranging the whole Hamiltonian immediately yields the coefficient of QUBO models \(\left\{{Q}_{ij}\right\}\).
Data availability
The datasets used and analysed during the current study available from the corresponding author on reasonable request.
References
Haxhimali, T., Karma, A., Gonzales, F. & Rappaz, M. Orientation selection in dendritic evolution. Nat. Mater. 5, 660–664 (2006).
Matsen, M. W. & Schick, M. Stable and unstable phases of a diblock copolymer melt. Phys. Rev. Lett. 72, 2660–2663 (1994).
Fish, J., Wagner, G. J. & Keten, S. Mesoscopic and multiscale modelling in materials. Nat. Mater. 20, 660–664 (2006).
Gee, R. H., Lacevic, N. & Fried, L. E. Atomistic simulations of spinodal phase separation preceding polymer crystallization. Nat. Mater. 5, 39–43 (2006).
Beardsley, T. M. & Matsen, M. W. Monte Carlo phase diagram for diblock copolymer melts. Eur. Phys. J. 32, 774–786 (2021).
Leibler, L. Theory of microphase separation in block copolymers. Macromolecules 13, 1602–1617 (1980).
Cheng, Q., Yang, X. & Shen, J. Efficient and accurate numerical schemes for a hydrodynamically coupled phase field diblock copolymer model. J. Comput. Phys. 341, 44–60 (2017).
Hsieh, M.T., Endo, B., Zhang, Y., Bauer, J. & Valdevit, L. The mechanical response of cellular materials with spinodal topologies. J. Mech. Phys. Solids 125, 401–419 (2019).
Kobayashi, R. Modeling and numerical simulations of dendritic crystal growth. Physica D 63, 410–423 (1993).
Kobayashi, R. A numerical approach to threedimensional dendritic solidification. Exp. Math. 3, 59–81 (1994).
Karma, A. & Rappel, W.J. Phasefield simulation of threedimensional dendrites: Is microscopic solvability theory correct? J. Cryst. Growth 174, 54–64 (1997).
Karma, A. & Rappel, W.J. Quantitative phasefield modeling of dendritic growth in two and three dimensions. Phys. Rev. E 57, 4323–4349 (1998).
Muramatsu, M., Aoyagi, Y., Tadano, Y. & Shizawa, K. Phasefield simulation of static recrystallization considering nucleation from subgrains and nucleus growth with incubation period. Comput. Mater. Sci. 87, 112–122 (2014).
Muramatsu, M., Yashiro, K., Kawada, T. & Terada, K. Simulation of ferroelastic phase formation using phasefield model. Int. J. Mech. Sci. 146–147, 462–474 (2018).
Cheng, L. & Tian, G. Y. Comparison of nondestructive testing methods on detection of delaminations in composites. J. Sens. 2012, 408437 (2012).
Momeni, K. et al. Multiscale computational understanding and growth of 2D materials: A review. npj Comput. Mater. 6, 22 (2020).
Shi, X., Huang, H., Cao, G. & Ma, X. Accelerating largescale phasefield simulations with GPU. AIP Adv. 7, 105216 (2017).
DeWitt, S., Rudraraju, S., Montiel, D., Andrews, W. B. & Thornton, K. PRISMSPF: A general framework for phasefield modeling with a matrixfree finite element method. npj Comput. Mater. 6, 29 (2020).
Zapiain, D. M. O., Stewart, J. A. & Dingreville, R. Accelerating phasefieldbased microstructure evolution predictions via surrogate models trained by machine learning methods. npj Comput. Mater. 7, 3 (2021).
Kadowaki, T. & Nishimori, H. Quantum annealing in the transverse Ising model. Phys. Rev. E 58, 5355–5363 (1998).
Johnson, M. W. et al. Quantum annealing with manufactured spins. Nature 473, 194–198 (2011).
Tanaka, S., Tamura, R. & Chakrabarti, B. Quantum Spin Glasses, Annealing and Computation (Cambridge Univ. Press, 2017).
Denchev, V. S. et al. What is the computational value of finiterange tunneling? Phys. Rev. X 6, 031015 (2016).
King, A. D. et al. Scaling advantage over pathintegral Monte Carlo in quantum simulation of geometrically frustrated magnets. Nat. Commun. 12, 1113 (2021).
Bando, Y. et al. Probing the universality of topological defect formation in a quantum annealer: KibbleZurek mechanism and beyond. Phys. Rev. Res. 2, 033369 (2020).
King, A. D. et al. Observation of topological phenomena in a programmable lattice of 1,800 qubits. Nature 560, 456–460 (2018).
Harris, R. et al. Phase transitions in a programmable quantum spin glass simulator. Science 361, 162–165 (2018).
Flory, P. J. Thermodynamics of high polymer solutions. J. Chem. Phys. 10, 51–61 (1942).
Huggins, M. L. Some properties of solutions of longchain compounds. J. Phys. Chem. 46, 151–158 (1942).
Ohta, T. & Kawasaki, K. Equilibrium morphology of block copolymer melts. Macromolecules 19, 2621–2632 (1986).
Cahn, J. W. & Hilliard, J. E. Free energy of a nonuniform system. I. Interfacial free energy. J. Chem. Phys. 28, 258–267 (1958).
https://amplify.fixstars.com/en/. Accessed 21 July 2021.
Acknowledgements
This work was supported by the Council for Science, Technology and Innovation (CSTI), Crossministerial Strategic Innovation Promotion Program (SIP), “Materials Integration for revolutionary design system of structural materials” (Funding agency: JST) and “Photonics and Quantum Technology for Society 5.0” (Funding agency: QST).
Author information
Authors and Affiliations
Contributions
K.E. conducted Data curation, Formal analysis, Investigation, Methodology, Software, Visualization, Validation, Writing—Original Draft, Writing—Review & Editing. Y.M. provided Methodology, Resources, Supervision. S.T. performed Methodology, Funding acquisition, Supervision. M.M. conducted Conceptualization, Funding acquisition, Project administration, Writing—Review & Editing, Supervision.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher's note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Endo, K., Matsuda, Y., Tanaka, S. et al. A phasefield model by an Ising machine and its application to the phaseseparation structure of a diblock polymer. Sci Rep 12, 10794 (2022). https://doi.org/10.1038/s41598022147354
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598022147354
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.