Preparation of Weakly Coupled Preparation of Weakly Coupled Spins within Molecules as 2qubit Spins within Molecules as 2qubit Quantum GatesQuantum Gates

Guillem AromíGroup of Magnetism and Functional Molecules (GMMF)

Universitat de Barcelona

QCPS-II 2010Orlando

Q-bits: |0 & |1

QuantumGates:

x

y

x

F(x)CNOT

control

target

Y

y

x

xSWAP

TWOINEQUIVALENT

Q-BITS

SWITCHABLEQ-BIT

INTERACTION

M. A. Nielsen, I. L. Chuang, Quantum Computing and Quantum Information, Cambridge University Press, Cambridge, 2000.

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1. Exhibit two well defined q-bits2. Possibility of initialize

3. Low decoherence (isolated from environment)4. Readable

6. Chemically Stable

5. Q-gate operations

M. N. Leuenberger, D. Loss, Nature 2001, 410, 789-793.

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Pairs of Metallic Wheelswith Tunable Coupling

Winpenny et al.Nature Nanotech., 2009, 4, 173

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OOO OOH OOO OOH OHO

OOO OOH OH OOO OOH OHOH

NOOO OOH OH

NOOO O

NN

H3L1 H4L2

H4L3 H5L4

H4L5 H2L6

Bis-Bis-ββ-diketonate Ligands-diketonate Ligands

Coord. Chem. Rev. 2008, 252, 964-989

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OOO OOH OHH4L3

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[Ni4(L3)2(py)6]

T / K

0 50 100 150 200 250 3000

1

2

3

4

5

J = −5.04

C. R. Chimie 2008, 11, 1117-1120

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OOO OO O

OOO OO O

CuII =

NiII =

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OOO OOH OHH4L3

Cu(AcO)2 / Ni(AcO)2 / NaH / py

[Ni2Cu2(L3)2(py)6]Chem., Eur. J. 2009, 15, 11235 – 11243

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T / K

0 50 100 150 200 250 300

MT

/ cm

3K

mol

-1

0.0

0.5

1.0

1.5

2.0

2.5

3.0

[Ni2Cu2(L3)2(py)6] J = −72.9 cm-1

θ = −0.5 KgNi = 2.46gCu = 2.10

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-Two weakly coupled, isolated S=1/2 spins

-Both equivalent (not CNOT) Interaction not Switcheable (not SWAP)

OOO OOH OHO

H4L2

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[Mn3O(AcO)6(py)3]+

O O

[Mn4O2(AcO)6(dbm)2]

OOO OOH OHOH4L2

Inorg. Chem. 2000, 39, 1501

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Inorg. Chem. 2007, 46, 9045

8.7 Å O

O

O

O

H3C

OH3C

O

RCO2- :

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MT /cm3 K mol−1

0 50 100 150 200 250 3000

1

2

3

4

5

6

7

8

T / K

Jpyz JttJbt

JbbJbtJbt

Jbt1

2

3

4

Inorg. Chem. 2007, 46, 9045

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-Two weakly coupled, isolated S=1/2 spins

-Both equivalent (not CNOT) Interaction not Switcheable (not SWAP)

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OOO OOH OHO

NNHNNHN

OH HON2H4

[Mn14O4(OH)2(OMe)4(OAc)2(L)2(HL)4(H2L)2(MeOH)2]

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H2L6N

OOO ONN

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NOOO O

NNH2L6

Co(AcO)2

and Co(NO3)2

in MeOH

[Co4(L6)2(MeOH)8]4+

Aust. J. Chem. 2009, 62, 1130-1136

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NOOO O

NN

(H2L6)

Co(AcO)2

and Co(NO3)2

in MeOH

N N+

[Co8(OH)4(NO3)3(L6)4(bpy)4(H2O)](NO3)

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Chem. Commun., 2011, 47, 707-709

-Two weakly coupled clusters with potentially tunable interactions

-Antiferromagnetic interactions cause an S = 0 on each cluster(not QuGate)

N OH

OOOOH

H3L7Ln(NO3)3

or LnCl3in pyridine

[Ln2(HL7)2(H2L7)(X)(solvents)x]

[Gd2(HL7)2(H2L7)Cl(H2O)(py)]

Inorg. Chem., 2010, 49, 6784–6786

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Ln = La, Ce, Pr, Nd, PmPm, Sm, Eu, Gd, Tb, Dy, Ho, Er,Tm, Yb, Lu

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Stark Level DepopulationWeak AF Coupling

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H

zzBzBzz HsgsgsJs 2211212H

0,0 0,2 0,4 0,6 0,8

-12

-8

-4

0

4

8

12

16

0,0 0,2 0,4 0,6 0,8

-8

-4

0

4

8

0,27 0,36 0,45

-3,6

-2,7

-1,8

energ

y (

K)

0H (T)

= 0 = 66 deg.

energ

y (

K)

0H (T)

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i) The total moment does not vanish at lowest temperatureii) There is a barrier to the reorientation of the total moment

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Specific Heat is consistent withNon-colinearity of the anisotropy axes of both ions in the dimer

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0,0 0,2 0,4 0,6 0,8

-8

-4

0

4

8 = 66 deg.

energ

y (K

)

0H (T)

REALIZATION REALIZATION OF A CNOT!!OF A CNOT!!

|1,1 → |1,0|1,0 → |1,1|0,1 → |0,1|0,0 → |0,0

|1,1

|1,0

|0,0

|0,1

h

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La Ce Pr NdPmSm Eu Gd Tb Dy Ho Er Tm Yb Lu

Y

Crystal structure of

33 complexes so far…

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Bis-β-diketonate ligands allow the synthesis of Magnetic Molecular Pairs of ClustersMagnetic Molecular Pairs of Clusters

An new Phenol/1,3-diketone/picolinic acid (H3L7) allows access of unsymmetrical [Lnunsymmetrical [Ln22]] complexes of virtually any lanthanide. Some of which meet the conditions for the realization of a CNOT QuGateCNOT QuGateH3L7 seems to allow the synthesis of heterometallic [LnLn’] heterometallic [LnLn’] complexes for virtually any pair of Lanthanides

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35

36

37

38

39

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