Abstract
The sign problem at nonzero chemical potential prohibits the use of importance sampling in lattice simulations. Since complex Langevin dynamics does not rely on importance sampling, it provides a potential solution. Recently it was shown that complex Langevin dynamics fails in the disordered phase in the case of the three-dimensional XY model, while it appears to work in the entire phase diagram in the case of the three-dimensional SU(3) spin model. Here we analyse this difference and argue that it is due to the presence of the nontrivial Haar measure in the SU(3) case, which has a stabilizing effect on the complexified dynamics. The freedom to modify and stabilize the complex Langevin process is discussed in some detail.
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References
P. de Forcrand, Simulating QCD at finite density, PoS(LAT2009)010 [arXiv:1005.0539] [INSPIRE].
G. Parisi, On complex probabilities, Phys. Lett. B 131 (1983) 393 [INSPIRE].
J.R. Klauder, Stochastic quantization, in: H. Mitter, C.B. Lang eds., Recent Developments in High-Energy Physics, Springer-Verlag, Wien (1983), pg. 351.
J.R. Klauder, A Langevin approach to fermion and quantum spin correlation functions, J. Phys. A 16 (1983) L317 [INSPIRE].
J.R. Klauder, Coherent state Langevin equations for canonical quantum systems with applications to the quantized hall effect, Phys. Rev. A 29 (1984) 2036 [INSPIRE].
J. Ambjørn and S. Yang, Numerical problems in applying the Langevin equation to complex effective actions, Phys. Lett. B 165 (1985) 140 [INSPIRE].
J. Ambjørn, M. Flensburg and C. Peterson, The complex Langevin equation and Monte Carlo simulations of actions with static charges, Nucl. Phys. B 275 (1986) 375 [INSPIRE].
J. Berges, S. Borsányi, D. Sexty and I.-O. Stamatescu, Lattice simulations of real-time quantum fields, Phys. Rev. D 75 (2007) 045007 [hep-lat/0609058] [INSPIRE].
J. Berges and D. Sexty, Real-time gauge theory simulations from stochastic quantization with optimized updating, Nucl. Phys. B 799 (2008) 306 [arXiv:0708.0779] [INSPIRE].
G. Aarts and F.A. James, On the convergence of complex Langevin dynamics: The Three-dimensional XY model at finite chemical potential, JHEP 08 (2010) 020 [arXiv:1005.3468] [INSPIRE].
G. Aarts, Can stochastic quantization evade the sign problem? The relativistic Bose gas at finite chemical potential, Phys. Rev. Lett. 102 (2009) 131601 [arXiv:0810.2089] [INSPIRE].
G. Aarts, Complex Langevin dynamics at finite chemical potential: mean field analysis in the relativistic Bose gas, JHEP 05 (2009) 052 [arXiv:0902.4686] [INSPIRE].
G. Aarts and K. Splittorff, Degenerate distributions in complex Langevin dynamics: one-dimensional QCD at finite chemical potential, JHEP 08 (2010) 017 [arXiv:1006.0332] [INSPIRE].
G. Aarts and F.A. James, Complex Langevin dynamics in the SU(3) spin model at nonzero chemical potential revisited, JHEP 01 (2012) 118 [arXiv:1112.4655] [INSPIRE].
G. Aarts, E. Seiler and I.-O. Stamatescu, The Complex Langevin method: When can it be trusted?, Phys. Rev. D 81 (2010) 054508 [arXiv:0912.3360] [INSPIRE].
G. Aarts, F.A. James, E. Seiler and I.-O. Stamatescu, Complex Langevin: Etiology and Diagnostics of its Main Problem, Eur. Phys. J. C 71 (2011) 1756 [arXiv:1101.3270] [INSPIRE].
D. Banerjee and S. Chandrasekharan, Finite size effects in the presence of a chemical potential: A study in the classical non-linear O(2) σ-model, Phys. Rev. D 81 (2010) 125007 [arXiv:1001.3648] [INSPIRE].
F. Karsch and H. Wyld, Complex Langevin simulation of the SU(3) spin model with nonzero chemical potential, Phys. Rev. Lett. 55 (1985) 2242 [INSPIRE].
N. Bilic, H. Gausterer and S. Sanielevici, Complex Langevin solution to an effective theory of lattice QCD, Phys. Rev. D 37 (1988) 3684 [INSPIRE].
C. Gattringer, Flux representation of an effective Polyakov loop model for QCD thermodynamics, Nucl. Phys. B 850 (2011) 242 [arXiv:1104.2503] [INSPIRE].
Y.D. Mercado and C. Gattringer, Monte Carlo simulation of the SU(3) spin model with chemical potential in a flux representation, Nucl. Phys. B 862 (2012) 737 [arXiv:1204.6074] [INSPIRE].
M. Fromm, J. Langelage, S. Lottini and O. Philipsen, The QCD deconfinement transition for heavy quarks and all baryon chemical potentials, JHEP 01 (2012) 042 [arXiv:1111.4953] [INSPIRE].
M. Fromm, J. Langelage, S. Lottini, M. Neuman and O. Philipsen, The silver blaze property for QCD with heavy quarks from the lattice, arXiv:1207.3005 [INSPIRE].
G. Aarts and I.-O. Stamatescu, Stochastic quantization at finite chemical potential, JHEP 09 (2008) 018 [arXiv:0807.1597] [INSPIRE].
G. Aarts, F.A. James, E. Seiler and I.-O. Stamatescu, Adaptive stepsize and instabilities in complex Langevin dynamics, Phys. Lett. B 687 (2010) 154 [arXiv:0912.0617] [INSPIRE].
E. Seiler, D. Sexty and I.-O. Stamatescu, Gauge cooling in complex Langevin for QCD with heavy quarks, arXiv:1211.3709 [INSPIRE].
B. Soderberg, On the complex Langevin equation, Nucl. Phys. B 295 (1988) 396 [INSPIRE].
H. Okamoto, K. Okano, L. Schulke and S. Tanaka, The role of a kernel in complex Langevin systems, Nucl. Phys. B 324 (1989) 684 [INSPIRE].
K. Okano, L. Schulke and B. Zheng, Complex Langevin simulation, Prog. Theor. Phys. Suppl. 111 (1993) 313 [INSPIRE].
J. Berges and I.-O. Stamatescu, Simulating nonequilibrium quantum fields with stochastic quantization techniques, Phys. Rev. Lett. 95 (2005) 202003 [hep-lat/0508030] [INSPIRE].
A. Duncan and M. Niedermaier, On the temporal breakdown of the complex Langevin method, arXiv:1205.0307 [INSPIRE].
D. Weingarten, Complex probabilities on R N as real probabilities on C N and an application to path integrals, Phys. Rev. Lett. 89 (2002) 240201 [quant-ph/0210195] [INSPIRE].
A. Friedman, Stochastic Differential Equations and Applications, Dover publications Inc., New York, U.S.A. (1975).
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ArXiv ePrint: 1212.5231
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Aarts, G., James, F.A., Pawlowski, J.M. et al. Stability of complex Langevin dynamics in effective models. J. High Energ. Phys. 2013, 73 (2013). https://doi.org/10.1007/JHEP03(2013)073
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DOI: https://doi.org/10.1007/JHEP03(2013)073