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Chin. Phys. B, 2026, Vol. 35(6): 060512    DOI: 10.1088/1674-1056/ae48c6
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Thermodynamic and real-time dynamic properties of complex Sachdev-Ye-Kitaev model

Sizheng Cao(曹思政)1, Xian-Hui Ge(葛先辉)1,†, and Yi-Cheng Rui(芮易成)1,2,3
1 Department of Physics, Shanghai University, Shanghai 200444, China;
2 Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, China;
3 School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
Abstract  We study the complex Sachdev–Ye–Kitaev (cSYK) model numerically and investigate the thermodynamic behavior of the cSYK model across varying chemical potentials. We discover that the cSYK model remarkably mirrors the first-order phase transition seen in the van der Waals–Maxwell system, culminating at a non-mean-field critical point with distinctively different critical exponents. We analyze in detail the similarity between the van der Waals phase transition and the cSYK model, and further explore the mechanism by which the chemical potential drives the phase transition in the system. Exact diagonalization at finite N resolves the conserved U(1) charge sectors, showing that the chemical potential reshapes the density of states. Within each charge sector we find a strong level repulsion, while mixing sectors shows a Poisson distribution. The normalized spectral form factor displays a clear dip-ramp-plateau at low temperature for the neutral case, whereas for non-vanishing chemical potential the ramp is weakened by finite N reweighting of small edge sectors and only becomes visible at relatively high temperatures. Real-time dynamics, analyzed via analytical continuation of Schwinger–Dyson equations, show rapid decay in the gapless phase and prolonged oscillation lifetimes in the gapped regime. Spectral functions imply a shift from a continuous to a discrete energy level distribution, emphasizing the critical role of chemical potential in shaping spectral properties.
Keywords:  complex SYK model      van der Waals transition      spectral form factor      real-time dynamics  
Received:  08 January 2026      Revised:  18 February 2026      Accepted manuscript online:  23 February 2026
PACS:  05.30.-d (Quantum statistical mechanics)  
  05.70.Fh (Phase transitions: general studies)  
  05.45.Mt (Quantum chaos; semiclassical methods)  
Fund: This work is partly supported by the National Natural Science Foundation of China (Grant Nos. 12275166 and 12311540141).
Corresponding Authors:  Xian-Hui Ge     E-mail:  gexh@shu.edu.cn

Cite this article: 

Sizheng Cao(曹思政), Xian-Hui Ge(葛先辉), and Yi-Cheng Rui(芮易成) Thermodynamic and real-time dynamic properties of complex Sachdev-Ye-Kitaev model 2026 Chin. Phys. B 35 060512

[1] Sachdev S and Ye J 1993 Phys. Rev. Lett. 70 3339
[2] Kitaev A 2015 A simple model of quantum holography talks at KITP, 7 April 2015 and 27 May 2015
[3] Maldacena J and Stanford D 2016 Phys. Rev. D 94 106002
[4] Jensen K 2016 Phys. Rev. Lett. 117 111601
[5] Maldacena J and Qi X L 2018 arXiv: 1804.00491[hep-th]
[6] García-García A M, Loureiro B, Romero-Bermudez A and Tezuka M 2018 Phys. Rev. Lett. 120 241603
[7] Chen X, Fan R, Chen Y, Zhai H and Zhang P 2017 Phys. Rev. Lett. 119 207603
[8] Azeyanagi T, Ferrari F and Massolo F I S 2018 Phys. Rev. Lett. 120 061602
[9] Wang Y and Chubukov A V 2020 Phys. Rev. Res. 2 033084
[10] Wang W, Davis A, Pan G, Wang Y and Meng Z Y 2021 Phys. Rev. B 103 195108
[11] Sahoo S, Lantagne-Hurtubise E, Plugge S and Franz M 2020 Phys. Rev. Res. 2 043049
[12] Gu Y, Kitaev A, Sachdev S and Tarnopolsky G 2020 J. High Energy Phys. 2020 157
[13] Jian S K, Swingle B and Xian Z Y 2021 J. High Energy Phys. 2021 14
[14] Cai W, Cao S, Ge X H, Matsumoto M and Sin S J 2022 Phys. Rev. D 106 106010
[15] Cao S and Ge X H 2024 Phys. Rev. D 110 046022
[16] Ge X H, Jian S K, Wang Y L, Xian Z Y and Yao H 2020 Phys. Rev. Res. 2 023366
[17] Cai W, Ge X H and Yang G H 2018 J. High Energy Phys. 2018 76
[18] García-García A M, Sa L, Verbaarschot J J M and Yin C 2024 Phys. Rev. D 109 105017
[19] García-García A M, Verbaarschot J J M and Zheng J P 2024 Phys. Rev. D 110 086010
[20] Dai X, Jian S K and Yao H 2019 Phys. Rev. B 100 235144
[21] Nayak P, Sonner J and Vielma M 2019 J. High Energy Phys. 2019 19
[22] Fu W, Gaiotto D, Maldacena J and Sachdev S 2017 Phys. Rev. D 95 026009
[23] Peng C, Spradlin M and Volovich A 2017 J. High Energy Phys. 2017 202
[24] Bulycheva K 2017 J. High Energy Phys. 2017 69
[25] Mertens T G and Turiaci G J 2019 J. High Energy Phys. 2019 127
[26] Cvetic M and Papadimitriou I 2016 J. High Energy Phys. 2016 8
[27] Afshar H, Gonzalez H A, Grumiller D and Vassilevich D 2020 Phys. Rev. D 101 086024
[28] Godet V and Marteau C 2020 J. High Energy Phys. 2020 20
[29] Chaturvedi P, Papadimitriou I, Song W and Yu B 2021 J. High Energy Phys. 2021 142
[30] Louw J C, Cao S and Ge X H 2023 Phys. Rev. D 108 086014
[31] Cotler J S, Gur-Ari G, Hanada M, Polchinski J, Saad P, Shenker S H, Stanford D, Streicher A and Tezuka M 2017 J. High Energy Phys. 2017 118
[32] Fu W and Sachdev S 2016 Phys. Rev. B 94 035135
[33] Ferrari F and Schaposnik Massolo F I 2019 Phys. Rev. D 100 026007
[34] Kubiznak D and Mann R B 2012 J. High Energy Phys. 2012 033
[35] Bhattacharya K and Majhi B R 2020 Phys. Rev. B 802 135224
[36] Lantagne-Hurtubise E, Li C and Franz M 2018 Phys. Rev. B 97 235124
[37] Cheng L, Ge X H and Sin S J 2014 J. High Energy Phys. 2014 83
[38] Wei S W and Liu Y X 2015 Phys. Rev. Lett. 115 111302
[39] Saad P, Shenker S H and Stanford D 2019 arXiv: 1806.06840[hep-th]
[40] Altland A and Bagrets D 2018 Nucl. Phys. B 930 45
[41] Liu J 2018 Phys. Rev. D 98 086026
[42] Wei C and Sedrakyan T A 2021 Phys. Rev. A 103 013323
[43] Plugge S, Lantagne-Hurtubise E and Franz M 2020 Phys. Rev. Lett. 124 221601
[44] Nosaka T and Numasawa T 2021 J. High Energy Phys. 2021 150
[45] Maldacena J and Milekhin A 2021 J. High Energy Phys. 2021 258
[46] Kitaev A and Suh S J 2018 J. High Energy Phys. 2018 183
[47] Nosaka T and Numasawa T 2020 J. High Energy Phys. 2020 81
[48] Tikhanovskaya M, Guo H, Sachdev S and Tarnopolsky G 2021 Phys. Rev. B 103 075141
[49] Louw J C and Kehrein S 2023 Phys. Rev. B 107 075132
[50] Berry M V and Robnik M 1984 J. Phys. A: Math. Gen. 17 2413
[51] Guhr T, Muller–Groeling A and Weidenm uller H A 1998 Phys. Rep. 299 189
[52] Bohigas O, Giannoni M J and Schmit C 1984 Phys. Rev. Lett. 52 1
[53] Haake F, Gnutzmann S and Ku M 2019 Quantum Signatures of Chaos, 4th edn. (Cham: Springer) pp. 123–130
[54] Qi X L and Zhang P 2020 J. High Energy Phys. 2020 129
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