Abstract
We perform a numerical optimization of the first ten nontrivial eigenvalues of the Neumann Laplacian for planar Euclidean domains. The optimization procedure is done via a gradient method, while the computation of the eigenvalues themselves is done by means of an efficient meshless numerical method which allows for the computation of the eigenvalues for large numbers of domains within a reasonable time frame. The Dirichlet problem, previously studied by Oudet using a different numerical method, is also studied and we obtain similar (but improved) results for a larger number of eigenvalues. These results reveal an underlying structure to the optimizers regarding symmetry and connectedness, for instance, but also show that there are exceptions to these preventing general results from holding.
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References
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Acknowledgements
P.R.S.A. was partially supported by FCT, Portugal, through the scholarship SFRH/BPD/47595/2008 and the project PTDC/MAT/105475/2008 and by Fundação Calouste Gulbenkian through program Estímulo à Investigação 2009. Both authors were partially supported by FCT’s project PTDC/MAT/101007/2008.
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Communicated by Enrique Zuazua.
Appendix
Appendix
i | λ 5 | λ 6 | λ 7 | λ 8 | ||||
---|---|---|---|---|---|---|---|---|
a i | b i | a i | b i | a i | b i | a i | b i | |
0 | 0.55438079 | 0.540969934 | 0.555917408 | 0.52402981 | ||||
1 | 0.013238729 | 0.0057015487 | −0.0254618108 | 0.20040578 | −0.0396571523 | 0.0142910591 | −0.133073983 | −0.237327033 |
2 | −0.077358408 | 0.092876235 | −0.0441431399 | −0.0456353393 | −0.0378443687 | −0.069786321 | 0.0524340446 | 0.0850167772 |
3 | −0.0051545105 | −0.0024247559 | −0.0573759273 | 0.023490155 | −0.0159573574 | 0.059561064 | −0.0123987019 | −0.0376173185 |
4 | 0.014513074 | 0.080309088 | −0.0106613347 | −0.0482010972 | −0.0563539206 | 0.0490047495 | −0.0260590608 | 0.00874912734 |
5 | −0.0060402322 | 0.0077267846 | 0.0138861761 | 0.000120165574 | −0.00279806649 | −0.00185896562 | −0.00308877567 | −0.00973987438 |
6 | 0.0080050385 | 0.0023040320 | 0.000823401662 | −0.00116176266 | 0.028061714 | 0.00907415168 | −0.00634415879 | 0.014659245 |
7 | −0.00041462756 | 0.0055027319 | 0.000493117601 | 0.000994308524 | −0.00621703077 | 0.00398846543 | −0.00742943607 | 0.00144421808 |
8 | 0.011735634 | −0.0056190380 | 0.00160548125 | −0.00108261442 | 0.00163688539 | 0.00365127087 | 0.0144983946 | 0.00753703381 |
9 | 0.0039973580 | 0.0034615840 | −0.0000526885146 | 0.000351429203 | 0.00321047409 | −0.00372583508 | −0.00642345426 | −0.013566282 |
10 | −0.00022151852 | −0.0026638205 | 0.000112772803 | −0.0000539188865 | 0.0066201419 | −0.00279887602 | −0.00391602052 | 0.0101569665 |
11 | 0.0027374112 | 0.00075580032 | −0.000110774901 | 0.000119156464 | −0.00362005727 | 0.000298194234 | 0.00186757844 | −0.00127916948 |
12 | −0.0017708460 | −0.0030278106 | −0.000109752183 | −0.000168572897 | −0.00258236878 | −0.00312578819 | 0.0024586174 | 0.00171021319 |
13 | 0.00096320890 | −0.0020044397 | 7.12030548×10−6 | −0.0000117806279 | 0.00193116396 | 0.0000971958322 | −0.00172422653 | −0.00153156433 |
14 | −0.000035727810 | 0.00044155670 | 7.24155168×10−6 | −3.84022077×10−6 | −0.00131702223 | −0.000360018056 | 0.00181204829 | 0.00094827332 |
15 | −0.00053585540 | −0.0017723963 | −4.96715037×10−6 | −3.61610015×10−6 | −0.00172076406 | 0.000688255022 | −0.00166054256 | −0.00127832356 |
16 | −0.00012345948 | 0.00096474668 | 3.08139935×10−7 | −2.03467268×10−7 | −0.00115709151 | 0.000109810932 | 0.000431561493 | 0.00130351922 |
17 | −0.0013188383 | −0.00070898727 | 1.33654316×10−7 | 1.43346737×10−7 | 0.00149459761 | 0.000610453469 | 0.0000346589834 | 0.000803396577 |
18 | 0.00022774519 | 0.000042899804 | −1.13982504×10−7 | 5.93369227×10−8 | −0.000305459945 | 0.00101611823 | 0.00188952975 | −0.00135359719 |
19 | −0.00050075176 | 0.000026338167 | −0.000427708258 | −0.000303869144 | −0.00221559806 | −0.000232152954 | ||
20 | −0.00016570749 | 0.00018779596 | 0.000678645943 | 0.000276590019 | 0.00103793066 | 0.000830350291 | ||
21 | 0.000569909436 | −0.000046937353 | −0.000313475612 | −0.000209535319 | ||||
22 | 0.0000654203457 | 0.0000144614045 | 0.000450916946 | −0.000139709455 | ||||
23 | −0.000351309674 | −0.000371289997 | −0.000211391115 | 0.0001928562 | ||||
24 | 0.000351733859 | −0.000136480239 | 0.000217311751 | −0.000318264501 |
i | λ 9 | λ 10 | λ 11 | λ 12 | ||||
---|---|---|---|---|---|---|---|---|
a i | b i | a i | b i | a i | b i | a i | b i | |
0 | 0.550655939 | 0.5595999481423 | 0.556134818 | 0.560041023 | ||||
1 | −0.0998751448 | 0.0773421852 | 0.0138865410279 | −0.008909759517606 | −0.0368731391 | 0.0239315354 | −0.0379604707 | 0.0121487257 |
2 | 0.0550157453 | −0.0430957094 | 0.002833319704712 | 0.002227574982416 | −0.0182053322 | 0.0378034906 | 0.0387729478 | 0.0507913179 |
3 | 0.0399594874 | 0.0593875966 | −0.008349328761967 | 0.0957550910192 | −0.00715126258 | −0.101591534 | −0.0015923326 | 0.00266165893 |
4 | 0.00142349384 | 0.0425900486 | 0.005723472594822 | −0.002967862015974 | −0.0297483526 | −0.0418656294 | −0.0146793258 | 0.0490107094 |
5 | −0.0139749255 | −0.0408617143 | 0.002652563387632 | 0.002447234406475 | 0.0241573412 | 0.011609453 | 0.00402780473 | −0.0090959291 |
6 | −0.00367223638 | 0.0134695479 | −0.004599950115557 | 0.02627159459515 | 0.0164630521 | −0.00243660354 | 0.0172020883 | −0.00377988974 |
7 | 0.0082532258 | 0.00455014924 | −0.002226983087317 | 0.000837603292585 | −0.00634085209 | 0.00454033198 | 0.000684280074 | 0.00988820653 |
8 | −0.00895830418 | 0.00176185763 | 0.00158099064617 | 0.00129569319721 | −0.00412733089 | 0.0136032862 | 0.0176838961 | 0.0101877652 |
9 | 0.00783739536 | 0.00272856592 | 0.000470007408465 | −0.00146767096302 | −0.00119221343 | −0.00583869131 | −0.00650954246 | −0.00231789514 |
10 | 0.00224548719 | −0.00470960161 | −0.00032089848269 | −0.0000433152786976 | −0.000348634021 | 0.0023618601 | 0.00215815089 | 0.000591548356 |
11 | −0.00333457231 | 0.00120461234 | −0.000417096748991 | −0.000549411311543 | −0.00458553797 | −0.000155987857 | 0.00268858702 | −0.000746677809 |
12 | 0.00200923924 | 0.00134340334 | 0.00118106640714 | −0.00326484110276 | 0.00156859838 | −0.00100931829 | 0.00277871992 | −0.00316449624 |
13 | −0.00128480877 | −0.00273791879 | 0.0000474565496931 | 0.0000106513746558 | 0.00246569204 | −0.000345244088 | −0.00204072395 | 0.00161161335 |
14 | 0.000462592585 | 0.00386907619 | −0.000325293746937 | −0.000447970381423 | −0.000674880003 | −0.00290011162 | −0.0000851755712 | −0.00180079941 |
15 | 0.00220397703 | −0.00328595287 | −0.0000233520418177 | −2.21572997176×10−6 | 0.000577306217 | 0.0013066555 | 0.000479952574 | −0.00218761547 |
16 | −0.00159326685 | 0.000960521718 | 0.000145484964248 | 0.0000270002808451 | −0.000130890779 | −0.000367319041 | −0.00119840099 | −0.00172733708 |
17 | 0.000330803919 | 0.000303830978 | 0.0000346822452809 | 0.0000929323504196 | −0.00153045766 | −0.0000950422371 | 0.00130704997 | 0.00124434852 |
18 | −0.000225563872 | −0.00129473302 | −0.000323698743562 | 0.000580384511426 | 0.000111369245 | 0.0000164522889 | −0.00102042771 | −0.00100033718 |
19 | −0.000189994632 | 0.000379332968 | 5.83949533850×10−6 | −3.49905606658×10−6 | 0.000181076275 | −0.000228614786 | −0.000755371705 | 0.0000336785202 |
20 | 0.00114449161 | 0.000603512001 | 0.0000728114477851 | 0.000158698077368 | 0.0000332405057 | −0.00075412169 | −0.000423177546 | 0.000174586669 |
21 | −0.00107566805 | −0.000685698552 | −6.75766392730×10−9 | 8.82905652608×10−9 | 0.0000453530838 | 0.000211630126 | 0.000529771728 | −0.000195846058 |
22 | −4.71286357457×10−9 | −1.34781200234×10−9 | 0.000790026567 | 0.00042327352 | −0.000711361356 | 0.000555750456 | ||
23 | 4.91209220912×10−9 | −1.56660058965×10−9 | −0.000395412526 | −0.0000237025238 | −0.000200059087 | 0.000361447102 | ||
24 | 1.34638456165×10−8 | −1.42615694109×10−8 | −0.000221380759 | 0.000184318601 | 6.73027374×10−6 | 0.000121028574 | ||
25 | −2.01122360346×10−9 | −3.63972837821×10−10 | ||||||
26 | −5.44330996748×10−9 | −6.68514460573×10−9 | ||||||
27 | 1.73465493720×10−9 | −1.98827703541×10−9 | ||||||
28 | 1.26990184897×10−9 | 6.02497710742×10−10 | ||||||
29 | −6.50409422882×10−10 | 5.20844861007×10−10 | ||||||
30 | −4.33794173095×10−9 | 2.75350252810×10−9 |
i | λ 13 | λ 14 | λ 15 | |||
---|---|---|---|---|---|---|
a i | b i | a i | b i | a i | b i | |
0 | 0.551503971 | 0.557612527 | 0.559420408 | |||
1 | −0.0338396841 | −0.114953381 | 0.0207678515 | −0.0631536572 | 6.04658369×10−6 | 0.0000124733917 |
2 | 0.0303279427 | −0.0574495473 | 0.058792891 | −0.00649772139 | −0.0000161762498 | 5.76792466×10−6 |
3 | −0.0130257251 | −0.0745641579 | 0.00531111557 | 0.0725253769 | −0.00258516561 | 0.098348305 |
4 | 0.00554729211 | 0.0470925562 | −0.0238412727 | 0.00370821936 | 0.0000123512599 | −0.000190815291 |
5 | −0.000623410989 | 0.0156226091 | −0.00423481014 | 0.0177123045 | −0.000180152753 | −0.000020711265 |
6 | 0.017655584 | 0.0236085722 | 0.0103355869 | 0.00370104625 | −0.0272911266 | −0.00107299012 |
7 | 0.0157809243 | 0.0041362414 | 0.00304837882 | −0.014888849 | 0.0000811807213 | 0.000119491243 |
8 | −0.0102727122 | 0.00626879621 | −0.00901708416 | −0.00469316105 | 0.0000417425306 | −0.000256107706 |
9 | 0.00478087159 | 0.0101645762 | −0.00164226506 | 0.0112119165 | 0.00153912059 | −0.0158989451 |
10 | −0.00238858367 | −0.00266695979 | 0.00355556561 | 0.00270396021 | −0.0000614558942 | −0.000447492308 |
11 | −0.00105832356 | −0.00408004353 | 0.000321931966 | −0.00139053897 | 0.000866001007 | 0.00027348823 |
12 | −0.000322435582 | −0.00132277381 | 0.000904139462 | −0.000968101304 | −0.00316306275 | −0.000317748954 |
13 | −0.000213314175 | −0.00418096453 | −0.000540135261 | 0.00109132915 | −0.000144984378 | −0.0000655946379 |
14 | 0.00272342258 | 0.000515668982 | 0.00225122256 | 0.00138225898 | 0.0000138295682 | 0.0000408821376 |
15 | 0.00227560059 | −0.00387180384 | 0.00168277384 | −0.00245914572 | 0.000674764382 | −0.00440846194 |
16 | −0.00134117822 | 0.000421056294 | −0.0020040944 | −0.00149449634 | 0.000187045993 | −0.0000389099159 |
17 | 0.00206300976 | 0.00168123748 | −0.00133504032 | 0.00121246955 | 0.000295365946 | 0.000120717313 |
18 | −0.000134937278 | −0.000594329311 | 0.000932926429 | 0.000698600595 | 0.00201216141 | 0.000363000545 |
19 | −0.000198444012 | 0.000832646684 | 0.000619420867 | −0.000348513148 | 0.0000688156095 | −0.0000196772322 |
20 | −0.00102360784 | 0.0000520444273 | −0.000149699453 | −0.000278429144 | −0.0000745226863 | 0.00023283672 |
21 | −0.001672364 | 0.000149383067 | −0.0000699271742 | −5.4335581×10−6 | 0.000139260778 | −0.000810604043 |
22 | −0.0000358586874 | 0.000530041321 | 0.0000435046984 | 0.0000790199395 | 0.0000853310383 | −0.0000589423176 |
23 | −0.000396920563 | −0.00174332362 | 0.000122963842 | −0.0000894017094 | −9.68881282×10−6 | −0.0000137876809 |
24 | −0.000877487074 | 0.000231158959 | −0.000096357168 | −0.000130817975 | 0.000859421574 | 0.000254606817 |
25 | 0.00081526229 | −0.0000801225237 | 0.000192873826 | 0.00041027021 | ||
26 | −0.0000126186682 | −0.000184605499 | −0.0000242683214 | 0.000159546939 | ||
27 | 0.000719525244 | 0.00045645044 | −0.0000380641833 | 0.0000291315401 | ||
28 | 0.0000402334404 | 0.0000752523567 | ||||
29 | −0.000231434094 | 0.000612933714 | ||||
30 | 0.000248027728 | 0.000375568407 |
i | μ 3 | μ 4 | μ 5 | |||
---|---|---|---|---|---|---|
a i | b i | a i | b i | a i | b i | |
0 | 0.549954737 | 0.554098864 | 0.560519732 | |||
1 | −0.000578925467 | 0.122335927 | 0.00784197933 | 0.00418017833 | 2.70058702×10−6 | −7.43462854×10−7 |
2 | 0.0268566607 | 0.000218577103 | −0.0567066976 | −0.085617596 | −2.82208992×10−6 | 0.0891304954 |
3 | 0.000496273706 | −0.119430145 | 0.0000940623335 | 0.00223713046 | −2.99864606×10−6 | 3.78746736×10−6 |
4 | 0.0393289299 | 0.000347273779 | −0.0418915905 | 0.1008615 | 0.0176267143 | −1.07708404×10−6 |
5 | 0.000137109558 | 0.0106100598 | −0.00119189439 | 0.000890469706 | 2.41171388×10−6 | 2.88093629×10−6 |
6 | 0.00283111302 | −0.000494884753 | −0.000628688812 | −0.000171550392 | −3.02951992×10−7 | 0.000287510816 |
7 | 0.000178562726 | 0.00858917695 | 0.000993259124 | 0.000551021581 | −1.89820251×10−6 | 1.35592844×10−6 |
8 | −0.0044258337 | −0.000117746227 | 0.00172088603 | 0.00189395041 | −0.0000537048883 | −3.03014709×10−7 |
9 | −0.000153351823 | −0.00245969402 | 0.0000211410532 | 0.000121738707 | 1.11865906×10−8 | 1.5845649×10−8 |
10 | 0.000262693154 | 0.00011309051 | 0.0000861800292 | −0.000464999058 | −7.95639895×10−10 | 1.16121376×10−8 |
11 | 0.0000273742248 | −0.000637837391 | −2.92218066×10−6 | 3.16893374×10−6 | −9.58692935×10−9 | 7.27334368×10−9 |
12 | 0.000277665815 | 0.000118370769 | 0.000038215104 | −1.87411565×10−6 | −1.01220124×10−8 | −2.3451735×10−10 |
13 | 4.89182689×10−7 | −1.22498345×10−6 | 5.19443562×10−7 | −6.26013908×10−6 | −8.39746687×10−10 | −1.23147374×10−9 |
14 | −7.17958187×10−7 | −5.83425372×10−7 | −2.72365156×10−8 | 4.12250759×10−8 | ||
15 | 9.84379966×10−7 | −1.28371466×10−6 | −3.8438191×10−7 | 1.2958845×10−7 | ||
16 | 1.0499127×10−6 | 3.93269146×10−7 | −1.20147834×10−7 | −8.02744085×10−8 | ||
17 | −5.21573808×10−8 | 1.3948447×10−7 | ||||
18 | 4.29340708×10−7 | −7.32876443×10−8 |
i | μ 6 | μ 7 | μ 8 | |||
---|---|---|---|---|---|---|
a i | b i | a i | b i | a i | b i | |
0 | 0.544423006 | 0.561303447 | 0.563472327 | |||
1 | 0.154549722 | 0.074592044 | −0.0296105015 | 0.00929288081 | −0.0135281387 | −0.0125695822 |
2 | −0.0238297433 | −0.0134221544 | 0.00292713876 | 0.000461527094 | −0.00100221576 | 0.000360922605 |
3 | 0.0465889872 | 0.0735117289 | −0.00581168985 | 0.00629595371 | −0.000758596993 | −0.00183183995 |
4 | 0.00798942924 | 0.0640407746 | 0.000521812939 | 0.000923350669 | 0.0108989574 | −0.00829182165 |
5 | −0.00631739792 | −0.018003381 | −0.00154983934 | 0.0094039286 | −0.000820543007 | −0.000308128932 |
6 | −0.0137357316 | 0.0204107763 | −0.00501494717 | 0.0700259021 | 0.000874631017 | −0.00117284521 |
7 | −0.0216354835 | 0.0151204116 | −0.00243458512 | −0.012367072 | −0.00888157387 | −0.00150292924 |
8 | −0.00906075347 | 0.00115927695 | 0.00113180953 | 0.000671399157 | 0.000674798064 | 0.000729850385 |
9 | −0.008733436 | 0.000345375567 | 0.00256031464 | 0.00298770473 | −0.0000147809707 | 0.000267662456 |
10 | 0.00229280469 | −0.00114925445 | 0.00279992286 | −0.000175531225 | −0.00054844287 | −0.000335737527 |
11 | 0.00315240014 | 0.00284257911 | 0.00354013286 | 0.00287589877 | 0.00119052948 | −0.000881687946 |
12 | −0.00163249012 | 0.00100770067 | 0.0137409909 | 0.000577609805 | 0.000195303616 | 0.0000981460855 |
13 | −0.0000192004444 | 0.00315093287 | −0.0052461102 | 0.00145050804 | 0.000174689747 | 0.000173203814 |
14 | −0.00187726514 | 0.0026655375 | 0.00146193752 | −0.0000610893421 | −0.00126202335 | −0.000458787859 |
15 | −0.00216069733 | 0.00147185804 | 0.00022791128 | −0.0021485341 | 0.0000822630097 | 0.000478005166 |
16 | −0.00226807794 | 0.00129214283 | −0.0000970608746 | 0.000143359763 | 1.09927346×10−6 | 0.0000300340072 |
17 | −0.00096819417 | −0.000488799805 | 0.000144426536 | −0.00032671668 | −9.92661542×10−6 | −2.66527939×10−6 |
18 | −0.000118656413 | −0.00018293087 | 0.0000407362083 | −0.000176673501 | 0.0000515695341 | −9.26540504×10−6 |
19 | −0.000192492127 | 0.0000493303754 | −0.0000273822824 | 0.000171666015 | −7.89252523×10−6 | −6.26345568×10−6 |
20 | 0.000263760246 | 0.000350170164 | 0.0000432423872 | −0.000127265244 | 2.41000428×10−6 | −2.3749484×10−6 |
21 | 1.16558991×10−6 | 4.96712883×10−6 | −5.85227252×10−6 | −6.79087762×10−6 | ||
22 | −1.63244689×10−6 | 6.47331955×10−6 | −3.33045158×10−6 | 7.49271783×10−6 | ||
23 | −3.4729084×10−6 | 5.95322586×10−6 | 1.88193258×10−6 | −3.98305519×10−7 | ||
24 | −4.96630548×10−6 | 1.72968518×10−6 | −2.36175431×10−18 | 2.51061885×10−7 | ||
25 | 5.12755036×10−8 | 2.14945715×10−7 | ||||
26 | −3.07397112×10−8 | 2.19743806×10−7 | ||||
27 | −6.99669598×10−8 | 1.77349366×10−7 |
i | μ 9 | μ 10 | ||
---|---|---|---|---|
a i | b i | a i | b i | |
0 | 0.546107642 | 0.557982648 | ||
1 | 0.132184562 | 0.0832860664 | −0.0107226947 | −0.00560550488 |
2 | −0.0422564242 | −0.081406976 | −0.00243459937 | 0.00272185071 |
3 | −0.00288494405 | 0.0494657212 | −0.106247514 | −0.0216645017 |
4 | −0.00990364257 | 0.0141660798 | 0.00371146609 | −0.00230659129 |
5 | 0.044032033 | −0.02072678 | 0.0000381990189 | 0.00245899729 |
6 | 0.0162253823 | 0.00284538146 | 0.0299771487 | 0.017040206 |
7 | −0.00684008357 | −0.00453911102 | −0.0033437228 | 0.00348204544 |
8 | 0.0113448501 | 0.0332865286 | 0.000299992113 | −0.00319195161 |
9 | −0.00329408749 | 0.0181081652 | −0.0217413819 | −0.0152507074 |
10 | −0.001807493 | 0.000642929037 | 0.000428329649 | 0.00273289835 |
11 | −0.00649512127 | 0.00171952483 | 0.000587136389 | −0.0000355914864 |
12 | 0.00379245547 | 0.00021410323 | 0.0000998793688 | −0.000710946153 |
13 | −0.000881363531 | −0.00148150927 | 0.00168461816 | −0.00141128391 |
14 | −0.00288415573 | −0.0106440172 | −0.000916519918 | 0.000996942438 |
15 | 0.000669513161 | −0.0000464470469 | 0.00151666691 | 0.00459881141 |
16 | 0.00163822411 | −0.000542216743 | −0.00150433091 | 0.000444760945 |
17 | 0.0087891035 | −0.00109922112 | 0.00109118785 | −0.000873399337 |
18 | 0.000888529246 | 0.000976724264 | −0.00103745245 | −0.00391413716 |
19 | 0.000561401536 | 0.00191176013 | 0.000136745573 | 0.000451314701 |
20 | 0.000172718181 | 0.00178646218 | −0.000328686271 | 0.0000923832995 |
21 | −0.0000607718052 | −0.00115913985 | 0.0000607676685 | 0.000247990695 |
22 | −0.00224226772 | 0.000812563001 | 0.000109497006 | −0.0000372289029 |
23 | −0.0026768554 | 0.0000114857432 | −0.0000756102401 | 0.0000118837984 |
24 | 0.00107005965 | −0.000253133326 | −0.000067632927 | 0.000143418041 |
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Antunes, P.R.S., Freitas, P. Numerical Optimization of Low Eigenvalues of the Dirichlet and Neumann Laplacians. J Optim Theory Appl 154, 235–257 (2012). https://doi.org/10.1007/s10957-011-9983-3
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DOI: https://doi.org/10.1007/s10957-011-9983-3