IP Library › Granted Patent US 12,288,131
Granted Patent B2
US 12,288,131 · App. 17/357,270 · Granted Apr 29, 2025

Quantum computing architecture based on entangled fermions

Inventors: Martin Zwierlein (Belmont, MA); Thomas Richard Hartke (Cambridge, MA); Ningyuan Jia (Cambridge, MA); Botond Oreg (Cambridge, MA)
Assignee: Massachusetts Institute of Technology
G06N10/40G01N21/6458G06N10/20G21K1/003G21K1/006
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Quick Facts
Patent No.
US 12,288,131
App. No.
17/357,270
Granted
Apr 29, 2025
Kind
B2
Abstract

Fermions are the building blocks of matter. Here, we disclose a robust quantum register composed of hundreds of fermionic atom pairs trapped in an optical lattice. With each fermion pair forming a spin-singlet, the qubit is realized as a set of near-degenerate, symmetry-protected two-particle wavefunctions describing common and relative motion. Degeneracy is lifted by the atomic recoil energy, which depends on mass and lattice wavelength, thereby rendering two-fermion motional qubits insensitive to noise of the confining potential. The quantum coherence can last longer than ten seconds. Universal control is provided by modulating interactions between the atoms. Via state-dependent, coherent conversion of free atom pairs into tightly bound molecules, we tune the speed of motional entanglement over three orders of magnitude, yielding 10 4 Ramsey oscillations within the coherence time. For site-resolved motional state readout, pairs are coherently split into their constituent fermions via a double-well, creating entangled Bell pairs.

Claims (34)

1. A method of storing quantum information, the method comprising:

trapping pairs of fermions in respective elongated harmonic potential wells formed in an optical lattice; and

initializing the pairs of fermions in a qubit basis comprising a first state and a second state separated by an energy difference depending on a geometry of the optical lattice.

2. The method of claim 1 , wherein the energy difference between the first state and the second state is equal to E r =ℏ 2 π 2 /(2ma z 2 ), where m is a mass of one fermion, a z is a spacing of the optical lattice in the z direction, and the elongated harmonic potential wells are elongated in the z direction.

3. The method of claim 1 , wherein the first state and the second state are vibrational states of the pairs of fermions.

4. The method of claim 1 , wherein the first state is an excited state for a center of mass motion and a ground state for relative motion of fermions in the pairs of fermions and the second state is a ground state for the center of mass motion and an excited state for relative motion of the fermions in the pairs of fermions.

5. The method of claim 1 , further comprising:

splitting one of the elongated harmonic potential wells into a double harmonic potential well; and

fluorescence imaging the pair of fermions in the double harmonic potential well.

6. The method of claim 1 , further comprising:

causing one of the pairs of fermions to undergo an avoided crossing between the first state and the second state.

7. The method of claim 6 , wherein causing one of the pairs of fermions to undergo the avoided crossing comprises ramping a magnetic field across the corresponding elongated harmonic potential well.

8. The method of claim 1 , further comprising:

modulating a magnetic field applied to the pairs of fermions to increase a coherence time of the pairs of fermions.

9. A system for storing quantum information, the system comprising:

a vacuum chamber to hold a fermionic gas;

a laser, in optical communication with the fermionic gas, to generate an optical lattice having elongated harmonic potential wells, each elongated harmonic potential well trapping one pair of fermions of the fermionic gas; and

a magnetic field source, in electromagnetic communication with the pairs of fermions, to ramp a magnetic field across the fermionic gas, the magnetic field initializing the pairs of fermions in a qubit basis comprising a first state and a second state separated by an energy difference depending on a geometry of the optical lattice.

10. The system of claim 9 , wherein the energy difference between the first state and the second state is equal to E r =ℏ 2 π 2 /(2ma z 2 ), where m is a mass of one fermion, a z is a spacing of the optical lattice in the z direction, and the elongated harmonic potential wells are elongated in the z direction.

11. The system of claim 9 , wherein the first state and the second state are vibrational states of the pairs of fermions.

12. The system of claim 9 , wherein the first state is an excited state for a center of mass motion and a ground state for relative motion of fermions in the pairs of fermion and the second state is a ground state for the center of mass motion and an excited state for relative motion of the fermions in the pairs of fermion.

13. The system of claim 9 , further comprising:

a detector, in optical communication with the pairs of fermions, to image fluorescence emitted by at least one of the pairs of fermions.

14. The system of claim 9 , wherein the magnetic field source is configured to ramp the magnetic field across one of elongated harmonic potential well to cause the corresponding pair of fermions to undergo an avoided crossing between the first state and the second state.

15. The system of claim 9 , wherein the magnetic field source is configured to modulate the magnetic field applied to the pairs of fermion to increase a coherence time of the pairs of fermion.

16. The system of claim 9 , wherein the laser is a first laser, and further comprising:

a second laser, in optical communication with the pairs of fermions, to illuminate at least one of the pairs of fermions with an optical tweezer beam.

17. A method of representing a qubit with a first quantum object and a second quantum object, the method comprising:

trapping the first quantum object and the second quantum object in a potential energy landscape realizing a potential well having quartic corrections, wherein energy corrections to the first quantum object and to the second quantum object due to the quartic corrections are independent of a magnitude scale factor of the potential energy landscape;

encoding a first state of the qubit with the first quantum object and the second quantum object in a first set of states of the potential well; and

encoding a second state of the qubit with the first quantum object and the second quantum object in a second set of states of the potential well.

18. The method of claim 17 , wherein the first quantum object comprises a first fermion and the second quantum object comprises a second fermion.

19. The method of claim 17 , wherein the first set of states of the potential well comprises a first motional state and a second motional state and the second set of states of the potential well comprises a third motional state and a fourth motional state different than the first motional state and second motional state.

20. The method of claim 17 , wherein energy levels of the states in the first set of states sum to a value equal to a sum of energy levels of the states in the second set of states, before including the quartic corrections.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 14, 2021
From: ZWIERLEIN, MARTIN; HARTKE, THOMAS RICHARD; JIA, NINGYUAN; OREG, BOTOND
To: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Reel/Frame 057798/0865 →
Continuity (2)
Provisional Application 63069279 · Aug 24, 2020
Related Publication 20240338583A1 · Oct 10, 2024
References Cited (33)
US 20200185120A1 · Keesling et al. · 2020 [cited by applicant]
R. B. Diener and T.-L. Ho, Phys. Rev. Lett. 96, 010402 (2006) (Year: 2006). [cited by examiner]
M. Köhl et al., Phys. Rev. Lett. 94, 080403 (2005) (Year: 2005). [cited by examiner]
D. B. M. Dickerscheid et al., 71, 043604 (2005) (Year: 2005). [cited by examiner]
C. Chin, et al., Rev. Mod. Phys. 82, 1225 (2010) (Year: 2010). [cited by examiner]
G. Zürn, et al., Fermionization of two distinguishable fermions, Phys. Rev. Lett. 108, 075303 (2012) (Year: 2012). [cited by examiner]
H. Levine, et al., Parallel implementation of high-fidelity multiqubit gates with neutral atoms, Phys. Rev. Lett. 123, 170503 (2019) (Year: 2019). [cited by examiner]
Bergeman et al., “Atom-atom scattering under cylindrical harmonic confinement: Numerical and analytic studies of the confinement induced resonance.” Physical Review Letters 91.16 (2003): 163201. 4 pages. [cited by applicant]
Busch et al., “Two cold atoms in a harmonic trap.” Foundations of Physics 28.4 (1998): 549-559. [cited by applicant]
Calarco et al., “Quantum gates with neutral atoms: Controlling collisional interactions in time-dependent traps.” Physical Review A 61.2 (2000): 022304. 11 pages. [cited by applicant]
Cheuk et al., “Observation of 2D fermionic Mott insulators of K 40 with single-site resolution.” Physical Review Letters 116.23 (2016): 235301. 5 pages. [cited by applicant]
Cheuk et al., “Observation of spatial charge and spin correlations in the 2D Fermi-Hubbard model.” Science 353.6305 (2016): 1260-1264. [cited by applicant]
Cheuk et al., “Quantum-gas microscope for fermionic atoms.” Physical Review Letters 114.19 (2015): 193001. 5 pages. [cited by applicant]
Eckert et al., “Quantum computing in optical microtraps based on the motional states of neutral atoms.” Physical Review A 66.4 (2002): 042317. 11 pages. [cited by applicant]
Haller et al., “Confinement-induced resonances in low-dimensional quantum systems.” Physical Review Letters 104.15 (2010): 153203. 4 pages. [cited by applicant]
Haller et al., “Realization of an excited, strongly correlated quantum gas phase.” Science 325.5945 (2009): 1224-1227. [cited by applicant]
Hartke et al., “Doublon-hole correlations and fluctuation thermometry in a Fermi-Hubbard gas.” arXiv preprint arXiv:2003.11669 (2020). 9 pages. [cited by applicant]
Hu et al., “Ramsey interferometry with trapped motional quantum states.” Communications Physics 1.1 (2018): 1-9. [cited by applicant]
Idziaszek et al., “Two atoms in an anisotropic harmonic trap.” Physical Review A 71.5 (2005): 050701. 4 pages. [cited by applicant]
Kestner et al., “Anharmonicity-induced resonances for ultracold atoms and their detection.” New Journal of Physics 12.5 (2010): 053016. 12 pages. [cited by applicant]
Mompart et al., “Quantum computing with spatially delocalized qubits.” Physical Review Letters 90.14 (2003): 147901. 4 pages. [cited by applicant]
Nichols et al., “Spin transport in a Mott insulator of ultracold fermions.” Science 363.6425 (2019): 383-387. [cited by applicant]
Olshanii, “Atomic scattering in the presence of an external confinement and a gas of impenetrable bosons.” Physical Review Letters 81.5 (1998): 938. 4 pages. [cited by applicant]
Peano et al., “Confinement-induced resonances for a two-component ultracold atom gas in arbitrary quasi-one-dimensional traps.” New Journal of Physics 7.1 (2005): 192. 23 pages. [cited by applicant]
Peng et al., “Confinement-induced resonance in quasi-one-dimensional systems under transversely anisotropic confinement.” Physical Review A 82.6 (2010): 063633. 6 pages. [cited by applicant]
Peng et al., “Confinement-induced resonances in anharmonic waveguides.” Physical Review A 84.4 (2011): 043619. 13 pages. [cited by applicant]
Saffman et al., “Quantum information with Rydberg atoms.” Reviews of Modern Physics 82.3 (2010): 2313. 51 pages. [cited by applicant]
Sala et al., “Coherent molecule formation in anharmonic potentials near confinement-induced resonances.” Physical Review Letters 110.20 (2013): 203202. 5 pages. [cited by applicant]
Sala et al., “Inelastic confinement-induced resonances in low-dimensional quantum systems.” Physical Review Letters 109.7 (2012): 073201. 5 pages. [cited by applicant]
Van Frank et al., “Interferometry with non-classical motional states of a Bose-Einstein condensate.” Nature Communications 5.1 (2014): 1-6. [cited by applicant]
Wang et al., “Coherent addressing of individual neutral atoms in a 3D optical lattice.” Physical Review Letters 115.4 (2015): 043003. 5 pages. [cited by applicant]
Weitenberg et al., “Quantum computation architecture using optical tweezers.” Physical Review A 84.3 (2011): 032322. 9 pages. [cited by applicant]
Zhang et al., “Confinement-induced resonances in quasi-one-dimensional traps with transverse anisotropy.” Physical Review A 83.5 (2011): 053615. 13 pages. [cited by applicant]