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17 results on '"Mruczkiewicz, W."'

1. Phase transitions in random circuit sampling

Author

Morvan, A., Villalonga, B., Mi, X., Mandrà, S., Bengtsson, A., Klimov, P. V., Chen, Z., Hong, S., Erickson, C., Drozdov, I. K., Chau, J., Laun, G., Movassagh, R., Asfaw, A., Brandão, L. T. A. N., Peralta, R., Abanin, D., Acharya, R., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Atalaya, J., Bardin, J. C., Bilmes, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chang, H.-S., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Barba, A. Del Toro, Demura, S., Paolo, A. Di, Dunsworth, A., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Burgos, L. Flores, Forati, E., Fowler, A. G., Foxen, B., Garcia, G., Genois, É., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Dau, A. Grajales, Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K.-M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Malone, F. D., Martin, O., Martin, S., McClean, J. R., McEwen, M., Miao, K. C., Mieszala, A., Montazeri, S., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Yuezhen, O’Brien, T. E., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rhodes, D. M., Rocque, C., Rosenberg, E., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Sivak, V., Skruzny, J., Smith, W. C., Somma, R. D., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Heidweiller, C. Vollgraff, White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Rieffel, E. G., Biswas, R., Babbush, R., Bacon, D., Hilton, J., Lucero, E., Neven, H., Megrant, A., Kelly, J., Roushan, P., Aleiner, I., Smelyanskiy, V., Kechedzhi, K., Chen, Y., and Boixo, S.

Published
2024
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2. Stable Quantum-Correlated Many Body States through Engineered Dissipation

Author

Mi, X., Michailidis, A. A., Shabani, S., Miao, K. C., Klimov, P. V., Lloyd, J., Rosenberg, E., Acharya, R., Aleiner, I., Andersen, T. I., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bardin, J. C., Bengtsson, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Chen, Z., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Dau, A. G., Debroy, D. M., Barba, A. Del Toro, Demura, S., Di Paolo, A., Drozdov, I. K., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Forati, L. F. Burgos E., Fowler, A. G., Foxen, B., Genois, E., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Kechedzhi, K., Khattar, T., Khezri, M., Kieferova, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K. -M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Locharla, A., Malone, F. D., Martin, O., McClean, J. R., McEwen, M., Mieszala, A., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., OBrien, T. E., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smith, W. C., Somma, R., Sterling, G., Strain, D., Szalay, M., Torres, A., Vidal, G., Villalonga, B., Heidweiller, C. V., White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Neven, H., Babbush, R., Bacon, D., Boixo, S., Hilton, J., Lucero, E., Megrant, A., Kelly, J., Chen, Y., Roushan, P., Smelyanskiy, V., and Abanin, D. A.

Subjects
Quantum Physics
Abstract

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Published
2023
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3. Phase transition in Random Circuit Sampling

Author

Morvan, A., Villalonga, B., Mi, X., Mandrà, S., Bengtsson, A., Klimov, P. V., Chen, Z., Hong, S., Erickson, C., Drozdov, I. K., Chau, J., Laun, G., Movassagh, R., Asfaw, A., Brandão, L. T. A. N., Peralta, R., Abanin, D., Acharya, R., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Atalaya, J., Bardin, J. C., Bilmes, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chang, H. S., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Barba, A. Del Toro, Demura, S., Di Paolo, A., Dunsworth, A., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Burgos, L. Flores, Forati, E., Fowler, A. G., Foxen, B., Garcia, G., Genois, E., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Dau, A. Grajales, Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K. -M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Malone, F. D., Martin, O., Martin, S., McClean, J. R., McEwen, M., Miao, K. C., Mieszala, A., Montazeri, S., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Yuezhen, O'Brien, T. E., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rhodes, D. M., Rosenberg, E., Rocque, C., Roushan, P., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Sivak, V., Skruzny, J., Smith, W. C., Somma, R. D., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Heidweiller, C. Vollgraff, White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Rieffel, E. G., Biswas, R., Babbush, R., Bacon, D., Hilton, J., Lucero, E., Neven, H., Megrant, A., Kelly, J., Aleiner, I., Smelyanskiy, V., Kechedzhi, K., Chen, Y., and Boixo, S.

Subjects
Quantum Physics
Abstract

Undesired coupling to the surrounding environment destroys long-range correlations on quantum processors and hinders the coherent evolution in the nominally available computational space. This incoherent noise is an outstanding challenge to fully leverage the computation power of near-term quantum processors. It has been shown that benchmarking Random Circuit Sampling (RCS) with Cross-Entropy Benchmarking (XEB) can provide a reliable estimate of the effective size of the Hilbert space coherently available. The extent to which the presence of noise can trivialize the outputs of a given quantum algorithm, i.e. making it spoofable by a classical computation, is an unanswered question. Here, by implementing an RCS algorithm we demonstrate experimentally that there are two phase transitions observable with XEB, which we explain theoretically with a statistical model. The first is a dynamical transition as a function of the number of cycles and is the continuation of the anti-concentration point in the noiseless case. The second is a quantum phase transition controlled by the error per cycle; to identify it analytically and experimentally, we create a weak link model which allows varying the strength of noise versus coherent evolution. Furthermore, by presenting an RCS experiment with 67 qubits at 32 cycles, we demonstrate that the computational cost of our experiment is beyond the capabilities of existing classical supercomputers, even when accounting for the inevitable presence of noise. Our experimental and theoretical work establishes the existence of transitions to a stable computationally complex phase that is reachable with current quantum processors.

Published
2023
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4. Purification-based quantum error mitigation of pair-correlated electron simulations

Author

O'Brien, T. E., Anselmetti, G., Gkritsis, F., Elfving, V. E., Polla, S., Huggins, W. J., Oumarou, O., Kechedzhi, K., Abanin, D., Acharya, R., Aleiner, I., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bacon, D., Bardin, J. C., Bengtsson, A., Boixo, S., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chen, Y., Chen, Z., Chiaro, B., Chik, D., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Demura, S., Drozdov, I., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Burgos, L. Flores, Forati, E., Fowler, A. G., Foxen, B., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Dau, A. Grajales, Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hilton, J., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Kelly, J., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Klimov, P. V., Klots, A. R., Kothari, R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K., Laws, L., Lee, J., Lee, K., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Lucero, E., Malone, F. D., Mandra, S., Martin, O., Martin, S., McClean, J. R., McCourt, T., McEwen, M., Megrant, A., Mi, X., Mieszala, A., Miao, K. C., Mohseni, M., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Neven, H., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Roushan, P., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smelyanskiy, V., Smith, W. C., Somma, R., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Villalonga, B., Heidweiller, C. Vollgraff, White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Gogolin, C., Babbush, R., and Rubin, N. C.

Subjects
Quantum Physics
Abstract

An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems. Prior to fault-tolerant quantum computing, robust error mitigation strategies are necessary to continue this growth. Here, we study physical simulation within the seniority-zero electron pairing subspace, which affords both a computational stepping stone to a fully correlated model, and an opportunity to validate recently introduced ``purification-based'' error-mitigation strategies. We compare the performance of error mitigation based on doubling quantum resources in time (echo verification) or in space (virtual distillation), on up to $20$ qubits of a superconducting qubit quantum processor. We observe a reduction of error by one to two orders of magnitude below less sophisticated techniques (e.g. post-selection); the gain from error mitigation is seen to increase with the system size. Employing these error mitigation strategies enables the implementation of the largest variational algorithm for a correlated chemistry system to-date. Extrapolating performance from these results allows us to estimate minimum requirements for a beyond-classical simulation of electronic structure. We find that, despite the impressive gains from purification-based error mitigation, significant hardware improvements will be required for classically intractable variational chemistry simulations., Comment: 10 pages, 13 page supplementary material, 12 figures. Experimental data available at https://doi.org/10.5281/zenodo.7225821

Published
2022
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5. Purification-based quantum error mitigation of pair-correlated electron simulations

Author

O’Brien, T. E., Anselmetti, G., Gkritsis, F., Elfving, V. E., Polla, S., Huggins, W. J., Oumarou, O., Kechedzhi, K., Abanin, D., Acharya, R., Aleiner, I., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bardin, J. C., Bengtsson, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chen, Z., Chiaro, B., Chik, D., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Demura, S., Drozdov, I., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Flores Burgos, L., Forati, E., Fowler, A. G., Foxen, B., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Grajales Dau, A., Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Klimov, P. V., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K.-M., Laws, L., Lee, J., Lee, K., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Malone, F. D., Mandrà, S., Martin, O., Martin, S., McClean, J. R., McCourt, T., McEwen, M., Mi, X., Mieszala, A., Miao, K. C., Mohseni, M., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Roushan, P., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smith, W. C., Somma, R. D., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Villalonga, B., Vollgraff Heidweiller, C., White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Bacon, D., Boixo, S., Chen, Y., Hilton, J., Kelly, J., Lucero, E., Megrant, A., Neven, H., Smelyanskiy, V., Gogolin, C., Babbush, R., and Rubin, N. C.

Published
2023
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6. Formation of robust bound states of interacting microwave photons

Author

Morvan, A, Andersen, TI, Mi, X, Neill, C, Petukhov, A, Kechedzhi, K, Abanin, DA, Michailidis, A, Acharya, R, Arute, F, Arya, K, Asfaw, A, Atalaya, J, Bardin, JC, Basso, J, Bengtsson, A, Bortoli, G, Bourassa, A, Bovaird, J, Brill, L, Broughton, M, Buckley, BB, Buell, DA, Burger, T, Burkett, B, Bushnell, N, Chen, Z, Chiaro, B, Collins, R, Conner, P, Courtney, W, Crook, AL, Curtin, B, Debroy, DM, Del Toro Barba, A, Demura, S, Dunsworth, A, Eppens, D, Erickson, C, Faoro, L, Farhi, E, Fatemi, R, Flores Burgos, L, Forati, E, Fowler, AG, Foxen, B, Giang, W, Gidney, C, Gilboa, D, Giustina, M, Grajales Dau, A, Gross, JA, Habegger, S, Hamilton, MC, Harrigan, MP, Harrington, SD, Hoffmann, M, Hong, S, Huang, T, Huff, A, Huggins, WJ, Isakov, SV, Iveland, J, Jeffrey, E, Jiang, Z, Jones, C, Juhas, P, Kafri, D, Khattar, T, Khezri, M, Kieferová, M, Kim, S, Kitaev, AY, Klimov, PV, Klots, AR, Korotkov, AN, Kostritsa, F, Kreikebaum, JM, Landhuis, D, Laptev, P, Lau, K-M, Laws, L, Lee, J, Lee, KW, Lester, BJ, Lill, AT, Liu, W, Locharla, A, Malone, F, Martin, O, McClean, JR, McEwen, M, Meurer Costa, B, Miao, KC, Mohseni, M, Montazeri, S, Mount, E, Mruczkiewicz, W, Naaman, O, and Neeley, M

Subjects
Quantum Physics, Physical Sciences, Photons, Microwaves, Electrons, Fees and Charges, Reproduction, General Science & Technology
Abstract

Systems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles1. The lack of general solutions for the three-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multiparticle bound states2-9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five photons. We devise a phase-sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the idea that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit.

Published
2022

7. Realizing topologically ordered states on a quantum processor

Author

Satzinger, K. J., Liu, Y., Smith, A., Knapp, C., Newman, M., Jones, C., Chen, Z., Quintana, C., Mi, X., Dunsworth, A., Gidney, C., Aleiner, I., Arute, F., Arya, K., Atalaya, J., Babbush, R., Bardin, J. C., Barends, R., Basso, J., Bengtsson, A., Bilmes, A., Broughton, M., Buckley, B. B., Buell, D. A., Burkett, B., Bushnell, N., Chiaro, B., Collins, R., Courtney, W., Demura, S., Derk, A. R., Eppens, D., Erickson, C., Farhi, E., Foaro, L., Fowler, A. G., Foxen, B., Giustina, M., Greene, A., Gross, J. A., Harrigan, M. P., Harrington, S. D., Hilton, J., Hong, S., Huang, T., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Jeffrey, E., Jiang, Z., Kafri, D., Kechedzhi, K., Khattar, T., Kim, S., Klimov, P. V., Korotkov, A. N., Kostritsa, F., Landhuis, D., Laptev, P., Locharla, A., Lucero, E., Martin, O., McClean, J. R., McEwen, M., Miao, K. C., Mohseni, M., Montazeri, S., Mruczkiewicz, W., Mutus, J., Naaman, O., Neeley, M., Neill, C., Niu, M. Y., O'Brien, T. E., Opremcak, A., Pató, B., Petukhov, A., Rubin, N. C., Sank, D., Shvarts, V., Strain, D., Szalay, M., Villalonga, B., White, T. C., Yao, Z., Yeh, P., Yoo, J., Zalcman, A., Neven, H., Boixo, S., Megrant, A., Chen, Y., Kelly, J., Smelyanskiy, V., Kitaev, A., Knap, M., Pollmann, F., and Roushan, P.

Subjects
Quantum Physics, Condensed Matter - Strongly Correlated Electrons
Abstract

The discovery of topological order has revolutionized the understanding of quantum matter in modern physics and provided the theoretical foundation for many quantum error correcting codes. Realizing topologically ordered states has proven to be extremely challenging in both condensed matter and synthetic quantum systems. Here, we prepare the ground state of the toric code Hamiltonian using an efficient quantum circuit on a superconducting quantum processor. We measure a topological entanglement entropy near the expected value of $\ln2$, and simulate anyon interferometry to extract the braiding statistics of the emergent excitations. Furthermore, we investigate key aspects of the surface code, including logical state injection and the decay of the non-local order parameter. Our results demonstrate the potential for quantum processors to provide key insights into topological quantum matter and quantum error correction., Comment: 6 pages 4 figures, plus supplementary materials

Published
2021
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8. Accurately computing electronic properties of a quantum ring

Author

Neill, C., McCourt, T., Mi, X., Jiang, Z., Niu, M. Y., Mruczkiewicz, W., Aleiner, I., Arute, F., Arya, K., Atalaya, J., Babbush, R., Bardin, J. C., Barends, R., Bengtsson, A., Bourassa, A., Broughton, M., Buckley, B. B., Buell, D. A., Burkett, B., Bushnell, N., Campero, J., Chen, Z., Chiaro, B., Collins, R., Courtney, W., Demura, S., Derk, A. R., Dunsworth, A., Eppens, D., Erickson, C., Farhi, E., Fowler, A. G., Foxen, B., Gidney, C., Giustina, M., Gross, J. A., Harrigan, M. P., Harrington, S. D., Hilton, J., Ho, A., Hong, S., Huang, T., Huggins, W. J., Isakov, S. V., Jacob-Mitos, M., Jeffrey, E., Jones, C., Kafri, D., Kechedzhi, K., Kelly, J., Kim, S., Klimov, P. V., Korotkov, A. N., Kostritsa, F., Landhuis, D., Laptev, P., Lucero, E., Martin, O., McClean, J. R., McEwen, M., Megrant, A., Miao, K. C., Mohseni, M., Mutus, J., Naaman, O., Neeley, M., Newman, M., O'Brien, T. E., Opremcak, A., Ostby, E., Pato, B., Petukhov, A., Quintana, C., Redd, N., Rubin, N. C., Sank, D., Satzinger, K. J., Shvarts, V., Strain, D., Szalay, M., Trevithick, M. D., Villalonga, B., White, T. C., Yao, Z., Yeh, P., Zalcman, A., Neven, H., Boixo, S., Ioffe, L. B., Roushan, P., Chen, Y., and Smelyanskiy, V.

Subjects
Quantum Physics
Abstract

A promising approach to study condensed-matter systems is to simulate them on an engineered quantum platform. However, achieving the accuracy needed to outperform classical methods has been an outstanding challenge. Here, using eighteen superconducting qubits, we provide an experimental blueprint for an accurate condensed-matter simulator and demonstrate how to probe fundamental electronic properties. We benchmark the underlying method by reconstructing the single-particle band-structure of a one-dimensional wire. We demonstrate nearly complete mitigation of decoherence and readout errors and arrive at an accuracy in measuring energy eigenvalues of this wire with an error of ~0.01 rad, whereas typical energy scales are of order 1 rad. Insight into this unprecedented algorithm fidelity is gained by highlighting robust properties of a Fourier transform, including the ability to resolve eigenenergies with a statistical uncertainty of 1e-4 rad. Furthermore, we synthesize magnetic flux and disordered local potentials, two key tenets of a condensed-matter system. When sweeping the magnetic flux, we observe avoided level crossings in the spectrum, a detailed fingerprint of the spatial distribution of local disorder. Combining these methods, we reconstruct electronic properties of the eigenstates where we observe persistent currents and a strong suppression of conductance with added disorder. Our work describes an accurate method for quantum simulation and paves the way to study novel quantum materials with superconducting qubits.

Published
2020
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9. Accurately computing the electronic properties of a quantum ring

Author

Neill, C., McCourt, T., Mi, X., Jiang, Z., Niu, M. Y., Mruczkiewicz, W., Aleiner, I., Arute, I., Arya, K., Atalaya, J., Babbush, R., Bardin, J.C., Barends, R., Bengtsson, A., Bourasa, A., Broughton, M., and Buckley, B.B.

Subjects
Condensed matter physics -- Research, Quantum computing -- Research, Algorithms -- Usage, Algorithm, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

A promising approach to study condensed-matter systems is to simulate them on an engineered quantum platform.sup.1-4. However, the accuracy needed to outperform classical methods has not been achieved so far. Here, using 18 superconducting qubits, we provide an experimental blueprint for an accurate condensed-matter simulator and demonstrate how to investigate fundamental electronic properties. We benchmark the underlying method by reconstructing the single-particle band structure of a one-dimensional wire. We demonstrate nearly complete mitigation of decoherence and readout errors, and measure the energy eigenvalues of this wire with an error of approximately 0.01 rad, whereas typical energy scales are of the order of 1 rad. Insight into the fidelity of this algorithm is gained by highlighting the robust properties of a Fourier transform, including the ability to resolve eigenenergies with a statistical uncertainty of 10.sup.-4 rad. We also synthesize magnetic flux and disordered local potentials, which are two key tenets of a condensed-matter system. When sweeping the magnetic flux we observe avoided level crossings in the spectrum, providing a detailed fingerprint of the spatial distribution of local disorder. By combining these methods we reconstruct electronic properties of the eigenstates, observing persistent currents and a strong suppression of conductance with added disorder. Our work describes an accurate method for quantum simulation.sup.5,6 and paves the way to study new quantum materials with superconducting qubits. As a blueprint for high-precision quantum simulation, an 18-qubit algorithm that consists of more than 1,400 two-qubit gates is demonstrated, and reconstructs the energy eigenvalues of the simulated one-dimensional wire to a precision of 1 per cent., Author(s): C. Neill [sup.1] , T. McCourt [sup.1] , X. Mi [sup.1] , Z. Jiang [sup.1] , M. Y. Niu [sup.1] , W. Mruczkiewicz [sup.1] , I. Aleiner [sup.1] , [...]

Published
2021
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10. Stable Quantum-Correlated Many Body States via Engineered Dissipation

Author

Mi, X., Michailidis, A. A., Shabani, S., Miao, K. C., Klimov, P. V., Lloyd, J., Rosenberg, E., Acharya, R., Aleiner, I., Andersen, T. I., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bardin, J. C., Bengtsson, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Chen, Z., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Dau, A. G., Debroy, D. M., Barba, A. Del Toro, Demura, S., Di Paolo, A., Drozdov, I. K., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Forati, L. F. Burgos E., Fowler, A. G., Foxen, B., Genois, E., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Kechedzhi, K., Khattar, T., Khezri, M., Kieferova, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K. -M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Locharla, A., Malone, F. D., Martin, O., McClean, J. R., McEwen, M., Mieszala, A., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., OBrien, T. E., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smith, W. C., Somma, R., Sterling, G., Strain, D., Szalay, M., Torres, A., Vidal, G., Villalonga, B., Heidweiller, C. V., White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Neven, H., Babbush, R., Bacon, D., Boixo, S., Hilton, J., Lucero, E., Megrant, A., Kelly, J., Chen, Y., Roushan, P., Smelyanskiy, V., and Abanin, D. A.

Subjects
Quantum Physics, FOS: Physical sciences, Quantum Physics (quant-ph)
Abstract

Engineered dissipative reservoirs can steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using 49 superconducting qubits, we prepare low-energy states of the transverse-field Ising model via coupling to dissipative auxiliary qubits. In 1D, we observe long-range quantum correlations and a ground state fidelity that depends weakly on system sizes. In 2D, we find mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we discover a new spin transport regime in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors, and an essential tool for investigating nonequilibrium quantum phenomena.

Published
2023

11. Noise-resilient edge modes on a chain of superconducting qubits

Author

Mi, X., primary, Sonner, M., additional, Niu, M. Y., additional, Lee, K. W., additional, Foxen, B., additional, Acharya, R., additional, Aleiner, I., additional, Andersen, T. I., additional, Arute, F., additional, Arya, K., additional, Asfaw, A., additional, Atalaya, J., additional, Bardin, J. C., additional, Basso, J., additional, Bengtsson, A., additional, Bortoli, G., additional, Bourassa, A., additional, Brill, L., additional, Broughton, M., additional, Buckley, B. B., additional, Buell, D. A., additional, Burkett, B., additional, Bushnell, N., additional, Chen, Z., additional, Chiaro, B., additional, Collins, R., additional, Conner, P., additional, Courtney, W., additional, Crook, A. L., additional, Debroy, D. M., additional, Demura, S., additional, Dunsworth, A., additional, Eppens, D., additional, Erickson, C., additional, Faoro, L., additional, Farhi, E., additional, Fatemi, R., additional, Flores, L., additional, Forati, E., additional, Fowler, A. G., additional, Giang, W., additional, Gidney, C., additional, Gilboa, D., additional, Giustina, M., additional, Dau, A. G., additional, Gross, J. A., additional, Habegger, S., additional, Harrigan, M. P., additional, Hoffmann, M., additional, Hong, S., additional, Huang, T., additional, Huff, A., additional, Huggins, W. J., additional, Ioffe, L. B., additional, Isakov, S. V., additional, Iveland, J., additional, Jeffrey, E., additional, Jiang, Z., additional, Jones, C., additional, Kafri, D., additional, Kechedzhi, K., additional, Khattar, T., additional, Kim, S., additional, Kitaev, A. Y., additional, Klimov, P. V., additional, Klots, A. R., additional, Korotkov, A. N., additional, Kostritsa, F., additional, Kreikebaum, J. M., additional, Landhuis, D., additional, Laptev, P., additional, Lau, K.-M., additional, Lee, J., additional, Laws, L., additional, Liu, W., additional, Locharla, A., additional, Martin, O., additional, McClean, J. R., additional, McEwen, M., additional, Meurer Costa, B., additional, Miao, K. C., additional, Mohseni, M., additional, Montazeri, S., additional, Morvan, A., additional, Mount, E., additional, Mruczkiewicz, W., additional, Naaman, O., additional, Neeley, M., additional, Neill, C., additional, Newman, M., additional, O’Brien, T. E., additional, Opremcak, A., additional, Petukhov, A., additional, Potter, R., additional, Quintana, C., additional, Rubin, N. C., additional, Saei, N., additional, Sank, D., additional, Sankaragomathi, K., additional, Satzinger, K. J., additional, Schuster, C., additional, Shearn, M. J., additional, Shvarts, V., additional, Strain, D., additional, Su, Y., additional, Szalay, M., additional, Vidal, G., additional, Villalonga, B., additional, Vollgraff-Heidweiller, C., additional, White, T., additional, Yao, Z., additional, Yeh, P., additional, Yoo, J., additional, Zalcman, A., additional, Zhang, Y., additional, Zhu, N., additional, Neven, H., additional, Bacon, D., additional, Hilton, J., additional, Lucero, E., additional, Babbush, R., additional, Boixo, S., additional, Megrant, A., additional, Chen, Y., additional, Kelly, J., additional, Smelyanskiy, V., additional, Abanin, D. A., additional, and Roushan, P., additional

Published
2022
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12. Realizing topologically ordered states on a quantum processor

Author

Satzinger, K. J., primary, Liu, Y.-J, additional, Smith, A., additional, Knapp, C., additional, Newman, M., additional, Jones, C., additional, Chen, Z., additional, Quintana, C., additional, Mi, X., additional, Dunsworth, A., additional, Gidney, C., additional, Aleiner, I., additional, Arute, F., additional, Arya, K., additional, Atalaya, J., additional, Babbush, R., additional, Bardin, J. C., additional, Barends, R., additional, Basso, J., additional, Bengtsson, A., additional, Bilmes, A., additional, Broughton, M., additional, Buckley, B. B., additional, Buell, D. A., additional, Burkett, B., additional, Bushnell, N., additional, Chiaro, B., additional, Collins, R., additional, Courtney, W., additional, Demura, S., additional, Derk, A. R., additional, Eppens, D., additional, Erickson, C., additional, Faoro, L., additional, Farhi, E., additional, Fowler, A. G., additional, Foxen, B., additional, Giustina, M., additional, Greene, A., additional, Gross, J. A., additional, Harrigan, M. P., additional, Harrington, S. D., additional, Hilton, J., additional, Hong, S., additional, Huang, T., additional, Huggins, W. J., additional, Ioffe, L. B., additional, Isakov, S. V., additional, Jeffrey, E., additional, Jiang, Z., additional, Kafri, D., additional, Kechedzhi, K., additional, Khattar, T., additional, Kim, S., additional, Klimov, P. V., additional, Korotkov, A. N., additional, Kostritsa, F., additional, Landhuis, D., additional, Laptev, P., additional, Locharla, A., additional, Lucero, E., additional, Martin, O., additional, McClean, J. R., additional, McEwen, M., additional, Miao, K. C., additional, Mohseni, M., additional, Montazeri, S., additional, Mruczkiewicz, W., additional, Mutus, J., additional, Naaman, O., additional, Neeley, M., additional, Neill, C., additional, Niu, M. Y., additional, O’Brien, T. E., additional, Opremcak, A., additional, Pató, B., additional, Petukhov, A., additional, Rubin, N. C., additional, Sank, D., additional, Shvarts, V., additional, Strain, D., additional, Szalay, M., additional, Villalonga, B., additional, White, T. C., additional, Yao, Z., additional, Yeh, P., additional, Yoo, J., additional, Zalcman, A., additional, Neven, H., additional, Boixo, S., additional, Megrant, A., additional, Chen, Y., additional, Kelly, J., additional, Smelyanskiy, V., additional, Kitaev, A., additional, Knap, M., additional, Pollmann, F., additional, and Roushan, P., additional

Published
2021
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13. Dynamics of magnetization at infinite temperature in a Heisenberg spin chain.

Author

Rosenberg E, Andersen TI, Samajdar R, Petukhov A, Hoke JC, Abanin D, Bengtsson A, Drozdov IK, Erickson C, Klimov PV, Mi X, Morvan A, Neeley M, Neill C, Acharya R, Allen R, Anderson K, Ansmann M, Arute F, Arya K, Asfaw A, Atalaya J, Bardin JC, Bilmes A, Bortoli G, Bourassa A, Bovaird J, Brill L, Broughton M, Buckley BB, Buell DA, Burger T, Burkett B, Bushnell N, Campero J, Chang HS, Chen Z, Chiaro B, Chik D, Cogan J, Collins R, Conner P, Courtney W, Crook AL, Curtin B, Debroy DM, Barba ADT, Demura S, Di Paolo A, Dunsworth A, Earle C, Faoro L, Farhi E, Fatemi R, Ferreira VS, Burgos LF, Forati E, Fowler AG, Foxen B, Garcia G, Genois É, Giang W, Gidney C, Gilboa D, Giustina M, Gosula R, Dau AG, Gross JA, Habegger S, Hamilton MC, Hansen M, Harrigan MP, Harrington SD, Heu P, Hill G, Hoffmann MR, Hong S, Huang T, Huff A, Huggins WJ, Ioffe LB, Isakov SV, Iveland J, Jeffrey E, Jiang Z, Jones C, Juhas P, Kafri D, Khattar T, Khezri M, Kieferová M, Kim S, Kitaev A, Klots AR, Korotkov AN, Kostritsa F, Kreikebaum JM, Landhuis D, Laptev P, Lau KM, Laws L, Lee J, Lee KW, Lensky YD, Lester BJ, Lill AT, Liu W, Locharla A, Mandrà S, Martin O, Martin S, McClean JR, McEwen M, Meeks S, Miao KC, Mieszala A, Montazeri S, Movassagh R, Mruczkiewicz W, Nersisyan A, Newman M, Ng JH, Nguyen A, Nguyen M, Niu MY, O'Brien TE, Omonije S, Opremcak A, Potter R, Pryadko LP, Quintana C, Rhodes DM, Rocque C, Rubin NC, Saei N, Sank D, Sankaragomathi K, Satzinger KJ, Schurkus HF, Schuster C, Shearn MJ, Shorter A, Shutty N, Shvarts V, Sivak V, Skruzny J, Smith WC, Somma RD, Sterling G, Strain D, Szalay M, Thor D, Torres A, Vidal G, Villalonga B, Heidweiller CV, White T, Woo BWK, Xing C, Yao ZJ, Yeh P, Yoo J, Young G, Zalcman A, Zhang Y, Zhu N, Zobrist N, Neven H, Babbush R, Bacon D, Boixo S, Hilton J, Lucero E, Megrant A, Kelly J, Chen Y, Smelyanskiy V, Khemani V, Gopalakrishnan S, Prosen T, and Roushan P

Abstract

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Published
2024
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14. Stable quantum-correlated many-body states through engineered dissipation.

Author

Mi X, Michailidis AA, Shabani S, Miao KC, Klimov PV, Lloyd J, Rosenberg E, Acharya R, Aleiner I, Andersen TI, Ansmann M, Arute F, Arya K, Asfaw A, Atalaya J, Bardin JC, Bengtsson A, Bortoli G, Bourassa A, Bovaird J, Brill L, Broughton M, Buckley BB, Buell DA, Burger T, Burkett B, Bushnell N, Chen Z, Chiaro B, Chik D, Chou C, Cogan J, Collins R, Conner P, Courtney W, Crook AL, Curtin B, Dau AG, Debroy DM, Del Toro Barba A, Demura S, Di Paolo A, Drozdov IK, Dunsworth A, Erickson C, Faoro L, Farhi E, Fatemi R, Ferreira VS, Burgos LF, Forati E, Fowler AG, Foxen B, Genois É, Giang W, Gidney C, Gilboa D, Giustina M, Gosula R, Gross JA, Habegger S, Hamilton MC, Hansen M, Harrigan MP, Harrington SD, Heu P, Hoffmann MR, Hong S, Huang T, Huff A, Huggins WJ, Ioffe LB, Isakov SV, Iveland J, Jeffrey E, Jiang Z, Jones C, Juhas P, Kafri D, Kechedzhi K, Khattar T, Khezri M, Kieferová M, Kim S, Kitaev A, Klots AR, Korotkov AN, Kostritsa F, Kreikebaum JM, Landhuis D, Laptev P, Lau KM, Laws L, Lee J, Lee KW, Lensky YD, Lester BJ, Lill AT, Liu W, Locharla A, Malone FD, Martin O, McClean JR, McEwen M, Mieszala A, Montazeri S, Morvan A, Movassagh R, Mruczkiewicz W, Neeley M, Neill C, Nersisyan A, Newman M, Ng JH, Nguyen A, Nguyen M, Niu MY, O'Brien TE, Opremcak A, Petukhov A, Potter R, Pryadko LP, Quintana C, Rocque C, Rubin NC, Saei N, Sank D, Sankaragomathi K, Satzinger KJ, Schurkus HF, Schuster C, Shearn MJ, Shorter A, Shutty N, Shvarts V, Skruzny J, Smith WC, Somma R, Sterling G, Strain D, Szalay M, Torres A, Vidal G, Villalonga B, Heidweiller CV, White T, Woo BWK, Xing C, Yao ZJ, Yeh P, Yoo J, Young G, Zalcman A, Zhang Y, Zhu N, Zobrist N, Neven H, Babbush R, Bacon D, Boixo S, Hilton J, Lucero E, Megrant A, Kelly J, Chen Y, Roushan P, Smelyanskiy V, and Abanin DA

Abstract

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Published
2024
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15. Observing ground-state properties of the Fermi-Hubbard model using a scalable algorithm on a quantum computer.

Author

Stanisic S, Bosse JL, Gambetta FM, Santos RA, Mruczkiewicz W, O'Brien TE, Ostby E, and Montanaro A

Abstract

The famous, yet unsolved, Fermi-Hubbard model for strongly-correlated electronic systems is a prominent target for quantum computers. However, accurately representing the Fermi-Hubbard ground state for large instances may be beyond the reach of near-term quantum hardware. Here we show experimentally that an efficient, low-depth variational quantum algorithm with few parameters can reproduce important qualitative features of medium-size instances of the Fermi-Hubbard model. We address 1 × 8 and 2 × 4 instances on 16 qubits on a superconducting quantum processor, substantially larger than previous work based on less scalable compression techniques, and going beyond the family of 1D Fermi-Hubbard instances, which are solvable classically. Consistent with predictions for the ground state, we observe the onset of the metal-insulator transition and Friedel oscillations in 1D, and antiferromagnetic order in both 1D and 2D. We use a variety of error-mitigation techniques, including symmetries of the Fermi-Hubbard model and a recently developed technique tailored to simulating fermionic systems. We also introduce a new variational optimisation algorithm based on iterative Bayesian updates of a local surrogate model., (© 2022. The Author(s).)

Published
2022
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16. Time-crystalline eigenstate order on a quantum processor.

Author

Mi X, Ippoliti M, Quintana C, Greene A, Chen Z, Gross J, Arute F, Arya K, Atalaya J, Babbush R, Bardin JC, Basso J, Bengtsson A, Bilmes A, Bourassa A, Brill L, Broughton M, Buckley BB, Buell DA, Burkett B, Bushnell N, Chiaro B, Collins R, Courtney W, Debroy D, Demura S, Derk AR, Dunsworth A, Eppens D, Erickson C, Farhi E, Fowler AG, Foxen B, Gidney C, Giustina M, Harrigan MP, Harrington SD, Hilton J, Ho A, Hong S, Huang T, Huff A, Huggins WJ, Ioffe LB, Isakov SV, Iveland J, Jeffrey E, Jiang Z, Jones C, Kafri D, Khattar T, Kim S, Kitaev A, Klimov PV, Korotkov AN, Kostritsa F, Landhuis D, Laptev P, Lee J, Lee K, Locharla A, Lucero E, Martin O, McClean JR, McCourt T, McEwen M, Miao KC, Mohseni M, Montazeri S, Mruczkiewicz W, Naaman O, Neeley M, Neill C, Newman M, Niu MY, O'Brien TE, Opremcak A, Ostby E, Pato B, Petukhov A, Rubin NC, Sank D, Satzinger KJ, Shvarts V, Su Y, Strain D, Szalay M, Trevithick MD, Villalonga B, White T, Yao ZJ, Yeh P, Yoo J, Zalcman A, Neven H, Boixo S, Smelyanskiy V, Megrant A, Kelly J, Chen Y, Sondhi SL, Moessner R, Kechedzhi K, Khemani V, and Roushan P

Subjects
Phase Transition, Thermodynamics, Cold Temperature
Abstract

Quantum many-body systems display rich phase structure in their low-temperature equilibrium states 1 . However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases 2-8 that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC) 7,9-15 . Concretely, dynamical phases can be defined in periodically driven many-body-localized (MBL) systems via the concept of eigenstate order 7,16,17 . In eigenstate-ordered MBL phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, or from regimes in which the dynamics of a few select states can mask typical behaviour. Here we implement tunable controlled-phase (CPHASE) gates on an array of superconducting qubits to experimentally observe an MBL-DTC and demonstrate its characteristic spatiotemporal response for generic initial states 7,9,10 . Our work employs a time-reversal protocol to quantify the impact of external decoherence, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. Furthermore, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to studying non-equilibrium phases of matter on quantum processors., (© 2021. The Author(s).)

Published
2022
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17. Information scrambling in quantum circuits.

Author

Mi X, Roushan P, Quintana C, Mandrà S, Marshall J, Neill C, Arute F, Arya K, Atalaya J, Babbush R, Bardin JC, Barends R, Basso J, Bengtsson A, Boixo S, Bourassa A, Broughton M, Buckley BB, Buell DA, Burkett B, Bushnell N, Chen Z, Chiaro B, Collins R, Courtney W, Demura S, Derk AR, Dunsworth A, Eppens D, Erickson C, Farhi E, Fowler AG, Foxen B, Gidney C, Giustina M, Gross JA, Harrigan MP, Harrington SD, Hilton J, Ho A, Hong S, Huang T, Huggins WJ, Ioffe LB, Isakov SV, Jeffrey E, Jiang Z, Jones C, Kafri D, Kelly J, Kim S, Kitaev A, Klimov PV, Korotkov AN, Kostritsa F, Landhuis D, Laptev P, Lucero E, Martin O, McClean JR, McCourt T, McEwen M, Megrant A, Miao KC, Mohseni M, Montazeri S, Mruczkiewicz W, Mutus J, Naaman O, Neeley M, Newman M, Niu MY, O'Brien TE, Opremcak A, Ostby E, Pato B, Petukhov A, Redd N, Rubin NC, Sank D, Satzinger KJ, Shvarts V, Strain D, Szalay M, Trevithick MD, Villalonga B, White T, Yao ZJ, Yeh P, Zalcman A, Neven H, Aleiner I, Kechedzhi K, Smelyanskiy V, and Chen Y

Abstract

Interactions in quantum systems can spread initially localized quantum information into the exponentially many degrees of freedom of the entire system. Understanding this process, known as quantum scrambling, is key to resolving several open questions in physics. Here, by measuring the time-dependent evolution and fluctuation of out-of-time-order correlators, we experimentally investigate the dynamics of quantum scrambling on a 53-qubit quantum processor. We engineer quantum circuits that distinguish operator spreading and operator entanglement and experimentally observe their respective signatures. We show that whereas operator spreading is captured by an efficient classical model, operator entanglement in idealized circuits requires exponentially scaled computational resources to simulate. These results open the path to studying complex and practically relevant physical observables with near-term quantum processors.

Published
2021
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