biostudies-literatureChou MHUnited States Department of Defense | Defense Advanced Research Projects Agency (DARPA)DOE | SC | Basic Energy Sciences (BES)National Science Foundation (NSF)United States Department of Defense | United States Air Force | AFMC | Air Force Office of Scientific Research (AF Office of Scientific Research)United States Department of Defense | United States Army | U.S. Army Research, Development and Engineering Command | Army Research Office (ARO)1450https://www.ebi.ac.uk/biostudies/studies/S-EPMC11805963biostudies-literatureUnknown16(1)Mechanical systems have emerged as a compelling platform for applications in quantum information, leveraging advances in the control of phonons, the quanta of mechanical vibrations. Experiments have demonstrated the control and measurement of phonon states in mechanical resonators, and while dual-resonator entanglement has been demonstrated, more complex entangled states remain a challenge. Here, we demonstrate rapid multi-phonon entanglement generation and subsequent tomographic analysis, using a scalable platform comprising two surface acoustic wave resonators on separate substrates, each connected to a superconducting qubit. We synthesize a mechanical Bell state with a fidelity of F=0.872±0.002 , and a multi-phonon entangled N = 2 N00N state with a fidelity of F=0.748±0.008 . The compacNature communicationsDeterministic multi-phonon entanglement between two mechanical resonators on separate substrates.PMC11805963CON-80004392HR0011-24-9-0364FA9550-20-1-0270NNCI ECCS-2025633QLCI-2016136DMR-2011854W911NF2310077NQISRCQiao HJoshi YJAndersson GConner CRCleland ANMiller JMChou MHYan HGrebel JPovey RGWu XfalseDeterministic multi-phonon entanglement between two mechanical resonators on separate substrates.Mechanical systems have emerged as a compelling platform for applications in quantum information, leveraging advances in the control of phonons, the quanta of mechanical vibrations. Experiments have demonstrated the control and measurement of phonon states in mechanical resonators, and while dual-resonator entanglement has been demonstrated, more complex entangled states remain a challenge. Here, we demonstrate rapid multi-phonon entanglement generation and subsequent tomographic analysis, using a scalable platform comprising two surface acoustic wave resonators on separate substrates, each connected to a superconducting qubit. We synthesize a mechanical Bell state with a fidelity of F=0.872±0.002 , and a multi-phonon entangled N = 2 N00N state with a fidelity of F=0.748±0.008 . The compac2025-01-01T00:00:00Z2025 Feb2025-04-04T01:34:02.769Z2025-04-04T01:34:02.769ZS-EPMC118059633992012110.1038/s41467-025-56454-0